diff --git a/devel/trexio/EZFIO.cfg b/devel/trexio/EZFIO.cfg
index 9da5e95..e99dba9 100644
--- a/devel/trexio/EZFIO.cfg
+++ b/devel/trexio/EZFIO.cfg
@@ -10,3 +10,21 @@ doc: Name of the exported TREXIO file
 interface: ezfio, ocaml, provider
 default: None
 
+[export_rdm]
+type: logical
+doc: If True, export two-body reduced density matrix
+interface: ezfio, ocaml, provider
+default: False
+
+[export_ao_ints]
+type: logical
+doc: If True, export two-electron integrals in AO basis
+interface: ezfio, ocaml, provider
+default: False
+
+[export_mo_ints]
+type: logical
+doc: If True, export two-electron integrals in MO basis
+interface: ezfio, ocaml, provider
+default: True
+
diff --git a/devel/trexio/LIB b/devel/trexio/LIB
index f00d288..91c0923 100644
--- a/devel/trexio/LIB
+++ b/devel/trexio/LIB
@@ -1,2 +1,2 @@
--L/home/scemama/TREX/trexio/_install/lib -ltrexio
+-ltrexio
 
diff --git a/devel/trexio/NEED b/devel/trexio/NEED
index 0a886cf..1d6fc39 100644
--- a/devel/trexio/NEED
+++ b/devel/trexio/NEED
@@ -4,3 +4,4 @@ mo_one_e_ints
 mo_two_e_ints
 ao_two_e_ints
 ao_one_e_ints
+two_body_rdm
diff --git a/devel/trexio/export_trexio.irp.f b/devel/trexio/export_trexio.irp.f
index ef47fcf..3a9e7b8 100644
--- a/devel/trexio/export_trexio.irp.f
+++ b/devel/trexio/export_trexio.irp.f
@@ -1,4 +1,11 @@
 program export_trexio
+  implicit none
+  read_wf = .True.
+  SOFT_TOUCH read_wf
+  call run
+end
+
+subroutine run
   use trexio
   implicit none
   BEGIN_DOC
@@ -7,6 +14,7 @@ program export_trexio
 
   integer(8)                     :: f ! TREXIO file handle
   integer                        :: rc
+  double precision, allocatable  :: factor(:)
 
   print *, 'TREXIO file : '//trim(trexio_filename)
   print *, ''
@@ -30,6 +38,8 @@ program export_trexio
 ! Electrons
 ! ---------
 
+  print *, 'Electrons'
+
   rc = trexio_write_electron_up_num(f, elec_alpha_num)
   call check_success(rc)
 
@@ -40,6 +50,8 @@ program export_trexio
 ! Nuclei
 ! ------
 
+  print *, 'Nuclei'
+
   rc = trexio_write_nucleus_num(f, nucl_num)
   call check_success(rc)
 
@@ -52,10 +64,15 @@ program export_trexio
   rc = trexio_write_nucleus_label(f, nucl_label, 32)
   call check_success(rc)
 
+  rc = trexio_write_nucleus_repulsion(f, nuclear_repulsion)
+  call check_success(rc)
+
 
 ! Pseudo-potentials
 ! -----------------
 
+  print *, 'ECP'
+
   double precision, allocatable :: tmp_double(:,:)
   integer, allocatable          :: tmp_int(:,:)
 
@@ -94,39 +111,36 @@ program export_trexio
 ! Basis
 ! -----
 
+  print *, 'Basis'
+
+
   rc = trexio_write_basis_type(f, 'Gaussian', len('Gaussian'))
   call check_success(rc)
 
-  rc = trexio_write_basis_num(f, shell_num)
-  call check_success(rc)
-
-  rc = trexio_write_basis_nucleus_shell_num(f, nucleus_shell_num)
-  call check_success(rc)
-
-  rc = trexio_write_basis_nucleus_index(f, basis_nucleus_index)
-  call check_success(rc)
-
-  rc = trexio_write_basis_shell_ang_mom(f, shell_ang_mom)
-  call check_success(rc)
-
   rc = trexio_write_basis_prim_num(f, prim_num)
   call check_success(rc)
 
-  rc = trexio_write_basis_shell_prim_num(f, shell_prim_num)
-  call check_success(rc)
+   rc = trexio_write_basis_shell_num(f, shell_num)
+   call check_success(rc)
 
-  double precision, allocatable :: factor(:)
-  allocate(factor(shell_num))
-  if (ao_normalized) then
-    factor(1:shell_num) = shell_normalization_factor(1:shell_num)
-  else
-    factor(1:shell_num) = 1.d0
-  endif
-  rc = trexio_write_basis_shell_factor(f, factor)
-  call check_success(rc)
-  deallocate(factor)
+   rc = trexio_write_basis_nucleus_index(f, basis_nucleus_index)
+   call check_success(rc)
 
-  rc = trexio_write_basis_shell_prim_index(f, shell_prim_index)
+   rc = trexio_write_basis_shell_ang_mom(f, shell_ang_mom)
+   call check_success(rc)
+
+   allocate(factor(shell_num))
+   if (ao_normalized) then
+     factor(1:shell_num) = shell_normalization_factor(1:shell_num)
+   else
+     factor(1:shell_num) = 1.d0
+   endif
+   rc = trexio_write_basis_shell_factor(f, factor)
+   call check_success(rc)
+
+   deallocate(factor)
+
+  rc = trexio_write_basis_shell_index(f, shell_index)
   call check_success(rc)
 
   rc = trexio_write_basis_exponent(f, prim_expo)
@@ -146,10 +160,11 @@ program export_trexio
   deallocate(factor)
 
 
-
 ! Atomic orbitals
 ! ---------------
 
+  print *, 'AOs'
+
   rc = trexio_write_ao_num(f, ao_num)
   call check_success(rc)
 
@@ -168,7 +183,6 @@ program export_trexio
   C_A(3) = 0.d0
 
   allocate(factor(ao_num))
-  print *, ao_first_of_shell
   if (ao_normalized) then
     do i=1,ao_num
       l = ao_first_of_shell(ao_shell(i))
@@ -184,6 +198,8 @@ program export_trexio
 ! One-e AO integrals
 ! ------------------
 
+  print *, 'AO integrals'
+
   rc = trexio_write_ao_1e_int_overlap(f,ao_overlap)
   call check_success(rc)
 
@@ -204,10 +220,59 @@ program export_trexio
   rc = trexio_write_ao_1e_int_core_hamiltonian(f,ao_one_e_integrals)
   call check_success(rc)
 
+! Two-e AO integrals
+! ------------------
+
+  if (export_ao_ints) then
+    PROVIDE ao_two_e_integrals_in_map
+
+    integer(8), parameter :: BUFSIZE=10000_8
+    double precision :: eri_buffer(BUFSIZE), integral
+    integer(4) :: eri_index(4,BUFSIZE)
+    integer(8) :: icount, offset
+
+    double precision, external :: get_ao_two_e_integral
+
+
+    icount = 0_8
+    offset = 0_8
+    do l=1,ao_num
+      do k=1,ao_num
+        do j=l,ao_num
+          do i=k,ao_num
+            if (i==j .and. k<l) cycle
+            if (i<j) cycle
+            integral = get_ao_two_e_integral(i,j,k,l,ao_integrals_map)
+            if (integral == 0.d0) cycle
+            icount += 1_8
+            eri_buffer(icount) = integral
+            eri_index(1,icount) = i
+            eri_index(2,icount) = j
+            eri_index(3,icount) = k
+            eri_index(4,icount) = l
+            if (icount == BUFSIZE) then
+              rc = trexio_write_ao_2e_int_eri(f, offset, icount, eri_index, eri_buffer)
+              call check_success(rc)
+              icount = 0_8
+              offset += icount
+            end if
+          end do
+        end do
+      end do
+    end do
+
+    if (icount >= 0_8) then
+      rc = trexio_write_ao_2e_int_eri(f, offset, icount, eri_index, eri_buffer)
+      call check_success(rc)
+    end if
+  end if
+
 
 ! Molecular orbitals
 ! ------------------
 
+  print *, 'MOs'
+
 !  rc = trexio_write_mo_type(f, mo_label)
 !  call check_success(rc)
 
@@ -221,6 +286,8 @@ program export_trexio
 ! One-e MO integrals
 ! ------------------
 
+  print *, 'MO integrals'
+
   rc = trexio_write_mo_1e_int_kinetic(f,mo_kinetic_integrals)
   call check_success(rc)
 
@@ -234,22 +301,103 @@ program export_trexio
     rc = trexio_write_mo_1e_int_ecp_non_local(f,mo_pseudo_integrals_non_local)
     call check_success(rc)
   endif
-!
+
   rc = trexio_write_mo_1e_int_core_hamiltonian(f,one_e_dm_mo)
   call check_success(rc)
 
+! Two-e MO integrals
+! ------------------
 
-! RDM
-! ----
+  if (export_mo_ints) then
+    PROVIDE mo_two_e_integrals_in_map
 
-!  rc = trexio_write_rdm_one_e(f,one_e_dm_mo)
-!  call check_success(rc)
-!
-!  rc = trexio_write_rdm_one_e_up(f,one_e_dm_mo_alpha_average)
-!  call check_success(rc)
-!
-!  rc = trexio_write_rdm_one_e_dn(f,one_e_dm_mo_beta_average)
-!  call check_success(rc)
+    double precision, external :: mo_two_e_integral
+
+
+    icount = 0_8
+    offset = 0_8
+    do l=1,mo_num
+      do k=1,mo_num
+        do j=l,mo_num
+          do i=k,mo_num
+            if (i==j .and. k<l) cycle
+            if (i<j) cycle
+            integral = mo_two_e_integral(i,j,k,l)
+            if (integral == 0.d0) cycle
+            icount += 1_8
+            eri_buffer(icount) = integral
+            eri_index(1,icount) = i
+            eri_index(2,icount) = j
+            eri_index(3,icount) = k
+            eri_index(4,icount) = l
+            if (icount == BUFSIZE) then
+              rc = trexio_write_mo_2e_int_eri(f, offset, icount, eri_index, eri_buffer)
+              call check_success(rc)
+              icount = 0_8
+              offset += icount
+            end if
+          end do
+        end do
+      end do
+    end do
+
+    if (icount >= 0_8) then
+      rc = trexio_write_mo_2e_int_eri(f, offset, icount, eri_index, eri_buffer)
+      call check_success(rc)
+    end if
+  end if
+
+
+
+! One-e RDM
+! ---------
+
+  rc = trexio_write_rdm_1e(f,one_e_dm_mo)
+  call check_success(rc)
+
+  rc = trexio_write_rdm_1e_up(f,one_e_dm_mo_alpha_average)
+  call check_success(rc)
+
+  rc = trexio_write_rdm_1e_dn(f,one_e_dm_mo_beta_average)
+  call check_success(rc)
+
+
+! Two-e RDM
+! ---------
+
+  if (export_rdm) then
+    PROVIDE two_e_dm_mo
+
+    icount = 0_8
+    offset = 0_8
+    do l=1,mo_num
+      do k=1,mo_num
+        do j=1,mo_num
+          do i=1,mo_num
+            integral = two_e_dm_mo(i,j,k,l)
+            if (integral == 0.d0) cycle
+            icount += 1_8
+            eri_buffer(icount) = integral
+            eri_index(1,icount) = i
+            eri_index(2,icount) = j
+            eri_index(3,icount) = k
+            eri_index(4,icount) = l
+            if (icount == BUFSIZE) then
+              rc = trexio_write_rdm_2e(f, offset, icount, eri_index, eri_buffer)
+              call check_success(rc)
+              icount = 0_8
+              offset += icount
+            end if
+          end do
+        end do
+      end do
+    end do
+
+    if (icount >= 0_8) then
+      rc = trexio_write_rdm_2e(f, offset, icount, eri_index, eri_buffer)
+      call check_success(rc)
+    end if
+  end if
 
 
 ! ------------------------------------------------------------------------------
diff --git a/devel/trexio/trexio_f.f90 b/devel/trexio/trexio_f.f90
new file mode 100644
index 0000000..6cce3aa
--- /dev/null
+++ b/devel/trexio/trexio_f.f90
@@ -0,0 +1,3726 @@
+module trexio
+
+  use, intrinsic :: iso_c_binding
+  implicit none
+
+  integer, parameter :: trexio_exit_code = 4
+  integer, parameter :: trexio_backend = 4
+
+  character(kind=c_char), parameter :: TREXIO_DELIM = c_new_line
+
+integer(trexio_exit_code), parameter :: TREXIO_FAILURE                 = -1
+integer(trexio_exit_code), parameter :: TREXIO_SUCCESS                 = 0
+integer(trexio_exit_code), parameter :: TREXIO_INVALID_ARG_1           = 1
+integer(trexio_exit_code), parameter :: TREXIO_INVALID_ARG_2           = 2
+integer(trexio_exit_code), parameter :: TREXIO_INVALID_ARG_3           = 3
+integer(trexio_exit_code), parameter :: TREXIO_INVALID_ARG_4           = 4
+integer(trexio_exit_code), parameter :: TREXIO_INVALID_ARG_5           = 5
+integer(trexio_exit_code), parameter :: TREXIO_END                     = 6
+integer(trexio_exit_code), parameter :: TREXIO_READONLY                = 7
+integer(trexio_exit_code), parameter :: TREXIO_ERRNO                   = 8
+integer(trexio_exit_code), parameter :: TREXIO_INVALID_ID              = 9
+integer(trexio_exit_code), parameter :: TREXIO_ALLOCATION_FAILED       = 10
+integer(trexio_exit_code), parameter :: TREXIO_HAS_NOT                 = 11
+integer(trexio_exit_code), parameter :: TREXIO_INVALID_NUM             = 12
+integer(trexio_exit_code), parameter :: TREXIO_ATTR_ALREADY_EXISTS     = 13
+integer(trexio_exit_code), parameter :: TREXIO_DSET_ALREADY_EXISTS     = 14
+integer(trexio_exit_code), parameter :: TREXIO_OPEN_ERROR              = 15
+integer(trexio_exit_code), parameter :: TREXIO_LOCK_ERROR              = 16
+integer(trexio_exit_code), parameter :: TREXIO_UNLOCK_ERROR            = 17
+integer(trexio_exit_code), parameter :: TREXIO_FILE_ERROR              = 18
+integer(trexio_exit_code), parameter :: TREXIO_GROUP_READ_ERROR        = 19
+integer(trexio_exit_code), parameter :: TREXIO_GROUP_WRITE_ERROR       = 20
+integer(trexio_exit_code), parameter :: TREXIO_ELEM_READ_ERROR         = 21
+integer(trexio_exit_code), parameter :: TREXIO_ELEM_WRITE_ERROR        = 22
+integer(trexio_exit_code), parameter :: TREXIO_UNSAFE_ARRAY_DIM        = 23
+integer(trexio_exit_code), parameter :: TREXIO_ATTR_MISSING            = 24
+integer(trexio_exit_code), parameter :: TREXIO_DSET_MISSING            = 25
+integer(trexio_exit_code), parameter :: TREXIO_BACK_END_MISSING        = 26
+integer(trexio_exit_code), parameter :: TREXIO_INVALID_STR_LEN         = 30
+integer(trexio_exit_code), parameter :: TREXIO_INT_SIZE_OVERFLOW       = 31
+
+interface
+   subroutine trexio_string_of_error (error, string) bind(C, name='trexio_string_of_error_f')
+     use, intrinsic :: iso_c_binding
+     import
+     integer (trexio_exit_code), intent(in), value :: error
+     character, intent(out) :: string(128)
+   end subroutine trexio_string_of_error
+end interface
+
+integer(trexio_backend), parameter :: TREXIO_HDF5 = 0
+  integer(trexio_backend), parameter :: TREXIO_TEXT = 1
+! integer(trexio_backend), parameter :: TREXIO_JSON = 2
+  integer(trexio_backend), parameter :: TREXIO_INVALID_BACK_END = 2
+
+interface
+   logical function trexio_has_backend (back_end) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(4), intent(in), value :: back_end
+   end function trexio_has_backend
+end interface
+
+interface
+   integer(8) function trexio_open_c (filename, mode, backend, rc_open) bind(C, name="trexio_open")
+     use, intrinsic :: iso_c_binding
+     import
+     character(kind=c_char), dimension(*)       :: filename
+     character, intent(in), value               :: mode
+     integer(trexio_backend), intent(in), value :: backend
+     integer(trexio_exit_code), intent(out)     :: rc_open
+   end function trexio_open_c
+end interface
+
+interface
+   integer function trexio_set_one_based(trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_set_one_based
+end interface
+
+interface
+   integer function trexio_close (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_close
+end interface
+
+character(len = 12) :: TREXIO_PACKAGE_VERSION = "2.0.0"
+integer(4) :: TREXIO_VERSION_MAJOR = 2
+integer(4) :: TREXIO_VERSION_MINOR = 0
+integer(4) :: TREXIO_VERSION_PATCH = 0
+
+interface
+   integer function trexio_has_metadata_code_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_metadata_code_num
+end interface
+
+interface
+   integer function trexio_has_metadata_author_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_metadata_author_num
+end interface
+
+interface
+   integer function trexio_has_electron_up_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_electron_up_num
+end interface
+
+interface
+   integer function trexio_has_electron_dn_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_electron_dn_num
+end interface
+
+interface
+   integer function trexio_has_nucleus_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_nucleus_num
+end interface
+
+interface
+   integer function trexio_has_nucleus_repulsion (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_nucleus_repulsion
+end interface
+
+interface
+   integer function trexio_has_ecp_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ecp_num
+end interface
+
+interface
+   integer function trexio_has_basis_prim_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_prim_num
+end interface
+
+interface
+   integer function trexio_has_basis_shell_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_shell_num
+end interface
+
+interface
+   integer function trexio_has_ao_cartesian (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_cartesian
+end interface
+
+interface
+   integer function trexio_has_ao_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_num
+end interface
+
+interface
+   integer function trexio_has_mo_num (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_num
+end interface
+
+interface
+   integer function trexio_has_metadata_package_version (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_metadata_package_version
+end interface
+
+interface
+   integer function trexio_has_metadata_description (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_metadata_description
+end interface
+
+interface
+   integer function trexio_has_nucleus_point_group (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_nucleus_point_group
+end interface
+
+interface
+   integer function trexio_has_basis_type (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_type
+end interface
+
+interface
+   integer function trexio_has_mo_type (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_type
+end interface
+
+interface
+   integer function trexio_has_nucleus_charge (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_nucleus_charge
+end interface
+
+interface
+   integer function trexio_has_nucleus_coord (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_nucleus_coord
+end interface
+
+interface
+   integer function trexio_has_ecp_max_ang_mom_plus_1 (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ecp_max_ang_mom_plus_1
+end interface
+
+interface
+   integer function trexio_has_ecp_z_core (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ecp_z_core
+end interface
+
+interface
+   integer function trexio_has_ecp_ang_mom (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ecp_ang_mom
+end interface
+
+interface
+   integer function trexio_has_ecp_nucleus_index (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ecp_nucleus_index
+end interface
+
+interface
+   integer function trexio_has_ecp_exponent (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ecp_exponent
+end interface
+
+interface
+   integer function trexio_has_ecp_coefficient (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ecp_coefficient
+end interface
+
+interface
+   integer function trexio_has_ecp_power (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ecp_power
+end interface
+
+interface
+   integer function trexio_has_basis_nucleus_index (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_nucleus_index
+end interface
+
+interface
+   integer function trexio_has_basis_shell_ang_mom (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_shell_ang_mom
+end interface
+
+interface
+   integer function trexio_has_basis_shell_factor (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_shell_factor
+end interface
+
+interface
+   integer function trexio_has_basis_shell_index (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_shell_index
+end interface
+
+interface
+   integer function trexio_has_basis_exponent (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_exponent
+end interface
+
+interface
+   integer function trexio_has_basis_coefficient (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_coefficient
+end interface
+
+interface
+   integer function trexio_has_basis_prim_factor (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_basis_prim_factor
+end interface
+
+interface
+   integer function trexio_has_ao_shell (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_shell
+end interface
+
+interface
+   integer function trexio_has_ao_normalization (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_normalization
+end interface
+
+interface
+   integer function trexio_has_ao_1e_int_overlap (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_1e_int_overlap
+end interface
+
+interface
+   integer function trexio_has_ao_1e_int_kinetic (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_1e_int_kinetic
+end interface
+
+interface
+   integer function trexio_has_ao_1e_int_potential_n_e (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_1e_int_potential_n_e
+end interface
+
+interface
+   integer function trexio_has_ao_1e_int_ecp_local (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_1e_int_ecp_local
+end interface
+
+interface
+   integer function trexio_has_ao_1e_int_ecp_non_local (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_1e_int_ecp_non_local
+end interface
+
+interface
+   integer function trexio_has_ao_1e_int_core_hamiltonian (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_1e_int_core_hamiltonian
+end interface
+
+interface
+   integer function trexio_has_mo_coefficient (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_coefficient
+end interface
+
+interface
+   integer function trexio_has_mo_occupation (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_occupation
+end interface
+
+interface
+   integer function trexio_has_mo_1e_int_overlap (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_1e_int_overlap
+end interface
+
+interface
+   integer function trexio_has_mo_1e_int_kinetic (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_1e_int_kinetic
+end interface
+
+interface
+   integer function trexio_has_mo_1e_int_potential_n_e (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_1e_int_potential_n_e
+end interface
+
+interface
+   integer function trexio_has_mo_1e_int_ecp_local (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_1e_int_ecp_local
+end interface
+
+interface
+   integer function trexio_has_mo_1e_int_ecp_non_local (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_1e_int_ecp_non_local
+end interface
+
+interface
+   integer function trexio_has_mo_1e_int_core_hamiltonian (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_1e_int_core_hamiltonian
+end interface
+
+interface
+   integer function trexio_has_rdm_1e (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_rdm_1e
+end interface
+
+interface
+   integer function trexio_has_rdm_1e_up (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_rdm_1e_up
+end interface
+
+interface
+   integer function trexio_has_rdm_1e_dn (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_rdm_1e_dn
+end interface
+
+interface
+   integer function trexio_has_ao_2e_int_eri (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_2e_int_eri
+end interface
+
+interface
+   integer function trexio_has_ao_2e_int_eri_lr (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_ao_2e_int_eri_lr
+end interface
+
+interface
+   integer function trexio_has_mo_2e_int_eri (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_2e_int_eri
+end interface
+
+interface
+   integer function trexio_has_mo_2e_int_eri_lr (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_2e_int_eri_lr
+end interface
+
+interface
+   integer function trexio_has_rdm_2e (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_rdm_2e
+end interface
+
+interface
+   integer function trexio_has_rdm_2e_upup (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_rdm_2e_upup
+end interface
+
+interface
+   integer function trexio_has_rdm_2e_dndn (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_rdm_2e_dndn
+end interface
+
+interface
+   integer function trexio_has_rdm_2e_updn (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_rdm_2e_updn
+end interface
+
+interface
+   integer function trexio_has_metadata_code (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_metadata_code
+end interface
+
+interface
+   integer function trexio_has_metadata_author (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_metadata_author
+end interface
+
+interface
+   integer function trexio_has_nucleus_label (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_nucleus_label
+end interface
+
+interface
+   integer function trexio_has_mo_class (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_class
+end interface
+
+interface
+   integer function trexio_has_mo_symmetry (trex_file) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+   end function trexio_has_mo_symmetry
+end interface
+
+interface
+   integer function trexio_read_metadata_code_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_metadata_code_num_32
+end interface
+
+interface
+   integer function trexio_read_metadata_author_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_metadata_author_num_32
+end interface
+
+interface
+   integer function trexio_read_electron_up_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_electron_up_num_32
+end interface
+
+interface
+   integer function trexio_read_electron_dn_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_electron_dn_num_32
+end interface
+
+interface
+   integer function trexio_read_nucleus_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_nucleus_num_32
+end interface
+
+interface
+   integer function trexio_read_nucleus_repulsion_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: num
+   end function trexio_read_nucleus_repulsion_32
+end interface
+
+interface
+   integer function trexio_read_ecp_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_ecp_num_32
+end interface
+
+interface
+   integer function trexio_read_basis_prim_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_basis_prim_num_32
+end interface
+
+interface
+   integer function trexio_read_basis_shell_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_basis_shell_num_32
+end interface
+
+interface
+   integer function trexio_read_ao_cartesian_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_ao_cartesian_32
+end interface
+
+interface
+   integer function trexio_read_ao_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_ao_num_32
+end interface
+
+interface
+   integer function trexio_read_mo_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_mo_num_32
+end interface
+
+interface
+   integer function trexio_read_metadata_code_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_metadata_code_num_64
+end interface
+
+interface
+   integer function trexio_read_metadata_author_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_metadata_author_num_64
+end interface
+
+interface
+   integer function trexio_read_electron_up_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_electron_up_num_64
+end interface
+
+interface
+   integer function trexio_read_electron_dn_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_electron_dn_num_64
+end interface
+
+interface
+   integer function trexio_read_nucleus_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_nucleus_num_64
+end interface
+
+interface
+   integer function trexio_read_nucleus_repulsion_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: num
+   end function trexio_read_nucleus_repulsion_64
+end interface
+
+interface
+   integer function trexio_read_ecp_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_ecp_num_64
+end interface
+
+interface
+   integer function trexio_read_basis_prim_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_basis_prim_num_64
+end interface
+
+interface
+   integer function trexio_read_basis_shell_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_basis_shell_num_64
+end interface
+
+interface
+   integer function trexio_read_ao_cartesian_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_ao_cartesian_64
+end interface
+
+interface
+   integer function trexio_read_ao_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_ao_num_64
+end interface
+
+interface
+   integer function trexio_read_mo_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: num
+   end function trexio_read_mo_num_64
+end interface
+
+interface
+   integer function trexio_read_metadata_code_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_metadata_code_num
+end interface
+
+interface
+   integer function trexio_read_metadata_author_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_metadata_author_num
+end interface
+
+interface
+   integer function trexio_read_electron_up_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_electron_up_num
+end interface
+
+interface
+   integer function trexio_read_electron_dn_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_electron_dn_num
+end interface
+
+interface
+   integer function trexio_read_nucleus_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_nucleus_num
+end interface
+
+interface
+   integer function trexio_read_nucleus_repulsion (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: num
+   end function trexio_read_nucleus_repulsion
+end interface
+
+interface
+   integer function trexio_read_ecp_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_ecp_num
+end interface
+
+interface
+   integer function trexio_read_basis_prim_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_basis_prim_num
+end interface
+
+interface
+   integer function trexio_read_basis_shell_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_basis_shell_num
+end interface
+
+interface
+   integer function trexio_read_ao_cartesian (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_ao_cartesian
+end interface
+
+interface
+   integer function trexio_read_ao_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_ao_num
+end interface
+
+interface
+   integer function trexio_read_mo_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: num
+   end function trexio_read_mo_num
+end interface
+
+interface
+   integer function trexio_read_metadata_package_version_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_read_metadata_package_version")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_metadata_package_version_c
+end interface
+
+interface
+   integer function trexio_read_metadata_description_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_read_metadata_description")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_metadata_description_c
+end interface
+
+interface
+   integer function trexio_read_nucleus_point_group_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_read_nucleus_point_group")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_nucleus_point_group_c
+end interface
+
+interface
+   integer function trexio_read_basis_type_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_read_basis_type")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_basis_type_c
+end interface
+
+interface
+   integer function trexio_read_mo_type_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_read_mo_type")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_mo_type_c
+end interface
+
+interface
+   integer function trexio_read_nucleus_charge_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_nucleus_charge_32
+end interface
+
+interface
+   integer function trexio_read_nucleus_coord_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_nucleus_coord_32
+end interface
+
+interface
+   integer function trexio_read_ecp_max_ang_mom_plus_1_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_max_ang_mom_plus_1_32
+end interface
+
+interface
+   integer function trexio_read_ecp_z_core_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_z_core_32
+end interface
+
+interface
+   integer function trexio_read_ecp_ang_mom_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_ang_mom_32
+end interface
+
+interface
+   integer function trexio_read_ecp_nucleus_index_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_nucleus_index_32
+end interface
+
+interface
+   integer function trexio_read_ecp_exponent_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_exponent_32
+end interface
+
+interface
+   integer function trexio_read_ecp_coefficient_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_coefficient_32
+end interface
+
+interface
+   integer function trexio_read_ecp_power_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_power_32
+end interface
+
+interface
+   integer function trexio_read_basis_nucleus_index_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_basis_nucleus_index_32
+end interface
+
+interface
+   integer function trexio_read_basis_shell_ang_mom_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_basis_shell_ang_mom_32
+end interface
+
+interface
+   integer function trexio_read_basis_shell_factor_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_basis_shell_factor_32
+end interface
+
+interface
+   integer function trexio_read_basis_shell_index_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_basis_shell_index_32
+end interface
+
+interface
+   integer function trexio_read_basis_exponent_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_basis_exponent_32
+end interface
+
+interface
+   integer function trexio_read_basis_coefficient_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_basis_coefficient_32
+end interface
+
+interface
+   integer function trexio_read_basis_prim_factor_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_basis_prim_factor_32
+end interface
+
+interface
+   integer function trexio_read_ao_shell_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ao_shell_32
+end interface
+
+interface
+   integer function trexio_read_ao_normalization_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_ao_normalization_32
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_overlap_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_overlap_32
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_kinetic_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_kinetic_32
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_potential_n_e_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_potential_n_e_32
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_ecp_local_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_ecp_local_32
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_ecp_non_local_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_ecp_non_local_32
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_core_hamiltonian_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_core_hamiltonian_32
+end interface
+
+interface
+   integer function trexio_read_mo_coefficient_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_mo_coefficient_32
+end interface
+
+interface
+   integer function trexio_read_mo_occupation_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_mo_occupation_32
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_overlap_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_overlap_32
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_kinetic_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_kinetic_32
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_potential_n_e_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_potential_n_e_32
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_ecp_local_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_ecp_local_32
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_ecp_non_local_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_ecp_non_local_32
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_core_hamiltonian_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_core_hamiltonian_32
+end interface
+
+interface
+   integer function trexio_read_rdm_1e_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_rdm_1e_32
+end interface
+
+interface
+   integer function trexio_read_rdm_1e_up_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_rdm_1e_up_32
+end interface
+
+interface
+   integer function trexio_read_rdm_1e_dn_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(out) :: dset(*)
+   end function trexio_read_rdm_1e_dn_32
+end interface
+
+interface
+   integer function trexio_read_nucleus_charge_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_nucleus_charge_64
+end interface
+
+interface
+   integer function trexio_read_nucleus_coord_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_nucleus_coord_64
+end interface
+
+interface
+   integer function trexio_read_ecp_max_ang_mom_plus_1_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: dset(*)
+   end function trexio_read_ecp_max_ang_mom_plus_1_64
+end interface
+
+interface
+   integer function trexio_read_ecp_z_core_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: dset(*)
+   end function trexio_read_ecp_z_core_64
+end interface
+
+interface
+   integer function trexio_read_ecp_ang_mom_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: dset(*)
+   end function trexio_read_ecp_ang_mom_64
+end interface
+
+interface
+   integer function trexio_read_ecp_nucleus_index_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: dset(*)
+   end function trexio_read_ecp_nucleus_index_64
+end interface
+
+interface
+   integer function trexio_read_ecp_exponent_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ecp_exponent_64
+end interface
+
+interface
+   integer function trexio_read_ecp_coefficient_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ecp_coefficient_64
+end interface
+
+interface
+   integer function trexio_read_ecp_power_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: dset(*)
+   end function trexio_read_ecp_power_64
+end interface
+
+interface
+   integer function trexio_read_basis_nucleus_index_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: dset(*)
+   end function trexio_read_basis_nucleus_index_64
+end interface
+
+interface
+   integer function trexio_read_basis_shell_ang_mom_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: dset(*)
+   end function trexio_read_basis_shell_ang_mom_64
+end interface
+
+interface
+   integer function trexio_read_basis_shell_factor_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_basis_shell_factor_64
+end interface
+
+interface
+   integer function trexio_read_basis_shell_index_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: dset(*)
+   end function trexio_read_basis_shell_index_64
+end interface
+
+interface
+   integer function trexio_read_basis_exponent_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_basis_exponent_64
+end interface
+
+interface
+   integer function trexio_read_basis_coefficient_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_basis_coefficient_64
+end interface
+
+interface
+   integer function trexio_read_basis_prim_factor_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_basis_prim_factor_64
+end interface
+
+interface
+   integer function trexio_read_ao_shell_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: dset(*)
+   end function trexio_read_ao_shell_64
+end interface
+
+interface
+   integer function trexio_read_ao_normalization_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_normalization_64
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_overlap_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_overlap_64
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_kinetic_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_kinetic_64
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_potential_n_e_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_potential_n_e_64
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_ecp_local_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_ecp_local_64
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_ecp_non_local_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_ecp_non_local_64
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_core_hamiltonian_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_core_hamiltonian_64
+end interface
+
+interface
+   integer function trexio_read_mo_coefficient_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_coefficient_64
+end interface
+
+interface
+   integer function trexio_read_mo_occupation_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_occupation_64
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_overlap_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_overlap_64
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_kinetic_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_kinetic_64
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_potential_n_e_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_potential_n_e_64
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_ecp_local_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_ecp_local_64
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_ecp_non_local_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_ecp_non_local_64
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_core_hamiltonian_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_core_hamiltonian_64
+end interface
+
+interface
+   integer function trexio_read_rdm_1e_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_rdm_1e_64
+end interface
+
+interface
+   integer function trexio_read_rdm_1e_up_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_rdm_1e_up_64
+end interface
+
+interface
+   integer function trexio_read_rdm_1e_dn_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_rdm_1e_dn_64
+end interface
+
+interface
+   integer function trexio_read_nucleus_charge (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_nucleus_charge
+end interface
+
+interface
+   integer function trexio_read_nucleus_coord (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_nucleus_coord
+end interface
+
+interface
+   integer function trexio_read_ecp_max_ang_mom_plus_1 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_max_ang_mom_plus_1
+end interface
+
+interface
+   integer function trexio_read_ecp_z_core (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_z_core
+end interface
+
+interface
+   integer function trexio_read_ecp_ang_mom (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_ang_mom
+end interface
+
+interface
+   integer function trexio_read_ecp_nucleus_index (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_nucleus_index
+end interface
+
+interface
+   integer function trexio_read_ecp_exponent (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ecp_exponent
+end interface
+
+interface
+   integer function trexio_read_ecp_coefficient (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ecp_coefficient
+end interface
+
+interface
+   integer function trexio_read_ecp_power (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ecp_power
+end interface
+
+interface
+   integer function trexio_read_basis_nucleus_index (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_basis_nucleus_index
+end interface
+
+interface
+   integer function trexio_read_basis_shell_ang_mom (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_basis_shell_ang_mom
+end interface
+
+interface
+   integer function trexio_read_basis_shell_factor (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_basis_shell_factor
+end interface
+
+interface
+   integer function trexio_read_basis_shell_index (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_basis_shell_index
+end interface
+
+interface
+   integer function trexio_read_basis_exponent (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_basis_exponent
+end interface
+
+interface
+   integer function trexio_read_basis_coefficient (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_basis_coefficient
+end interface
+
+interface
+   integer function trexio_read_basis_prim_factor (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_basis_prim_factor
+end interface
+
+interface
+   integer function trexio_read_ao_shell (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(out) :: dset(*)
+   end function trexio_read_ao_shell
+end interface
+
+interface
+   integer function trexio_read_ao_normalization (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_normalization
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_overlap (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_overlap
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_kinetic (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_kinetic
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_potential_n_e (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_potential_n_e
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_ecp_local (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_ecp_local
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_ecp_non_local (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_ecp_non_local
+end interface
+
+interface
+   integer function trexio_read_ao_1e_int_core_hamiltonian (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_ao_1e_int_core_hamiltonian
+end interface
+
+interface
+   integer function trexio_read_mo_coefficient (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_coefficient
+end interface
+
+interface
+   integer function trexio_read_mo_occupation (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_occupation
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_overlap (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_overlap
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_kinetic (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_kinetic
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_potential_n_e (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_potential_n_e
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_ecp_local (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_ecp_local
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_ecp_non_local (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_ecp_non_local
+end interface
+
+interface
+   integer function trexio_read_mo_1e_int_core_hamiltonian (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_mo_1e_int_core_hamiltonian
+end interface
+
+interface
+   integer function trexio_read_rdm_1e (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_rdm_1e
+end interface
+
+interface
+   integer function trexio_read_rdm_1e_up (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_rdm_1e_up
+end interface
+
+interface
+   integer function trexio_read_rdm_1e_dn (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(out) :: dset(*)
+   end function trexio_read_rdm_1e_dn
+end interface
+
+interface
+   integer function trexio_read_ao_2e_int_eri (trex_file, &
+                                                     offset_file, buffer_size, &
+                                                     index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(out) :: value_sparse(*)
+   end function trexio_read_ao_2e_int_eri
+end interface
+
+interface
+   integer function trexio_read_ao_2e_int_eri_lr (trex_file, &
+                                                     offset_file, buffer_size, &
+                                                     index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(out) :: value_sparse(*)
+   end function trexio_read_ao_2e_int_eri_lr
+end interface
+
+interface
+   integer function trexio_read_mo_2e_int_eri (trex_file, &
+                                                     offset_file, buffer_size, &
+                                                     index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(out) :: value_sparse(*)
+   end function trexio_read_mo_2e_int_eri
+end interface
+
+interface
+   integer function trexio_read_mo_2e_int_eri_lr (trex_file, &
+                                                     offset_file, buffer_size, &
+                                                     index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(out) :: value_sparse(*)
+   end function trexio_read_mo_2e_int_eri_lr
+end interface
+
+interface
+   integer function trexio_read_rdm_2e (trex_file, &
+                                                     offset_file, buffer_size, &
+                                                     index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(out) :: value_sparse(*)
+   end function trexio_read_rdm_2e
+end interface
+
+interface
+   integer function trexio_read_rdm_2e_upup (trex_file, &
+                                                     offset_file, buffer_size, &
+                                                     index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(out) :: value_sparse(*)
+   end function trexio_read_rdm_2e_upup
+end interface
+
+interface
+   integer function trexio_read_rdm_2e_dndn (trex_file, &
+                                                     offset_file, buffer_size, &
+                                                     index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(out) :: value_sparse(*)
+   end function trexio_read_rdm_2e_dndn
+end interface
+
+interface
+   integer function trexio_read_rdm_2e_updn (trex_file, &
+                                                     offset_file, buffer_size, &
+                                                     index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(out) :: value_sparse(*)
+   end function trexio_read_rdm_2e_updn
+end interface
+
+interface
+   integer function trexio_read_ao_2e_int_eri_size (trex_file, &
+                                                          size_max) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: size_max
+   end function trexio_read_ao_2e_int_eri_size
+end interface
+
+interface
+   integer function trexio_read_ao_2e_int_eri_lr_size (trex_file, &
+                                                          size_max) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: size_max
+   end function trexio_read_ao_2e_int_eri_lr_size
+end interface
+
+interface
+   integer function trexio_read_mo_2e_int_eri_size (trex_file, &
+                                                          size_max) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: size_max
+   end function trexio_read_mo_2e_int_eri_size
+end interface
+
+interface
+   integer function trexio_read_mo_2e_int_eri_lr_size (trex_file, &
+                                                          size_max) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: size_max
+   end function trexio_read_mo_2e_int_eri_lr_size
+end interface
+
+interface
+   integer function trexio_read_rdm_2e_size (trex_file, &
+                                                          size_max) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: size_max
+   end function trexio_read_rdm_2e_size
+end interface
+
+interface
+   integer function trexio_read_rdm_2e_upup_size (trex_file, &
+                                                          size_max) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: size_max
+   end function trexio_read_rdm_2e_upup_size
+end interface
+
+interface
+   integer function trexio_read_rdm_2e_dndn_size (trex_file, &
+                                                          size_max) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: size_max
+   end function trexio_read_rdm_2e_dndn_size
+end interface
+
+interface
+   integer function trexio_read_rdm_2e_updn_size (trex_file, &
+                                                          size_max) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(out) :: size_max
+   end function trexio_read_rdm_2e_updn_size
+end interface
+
+interface
+   integer function trexio_read_metadata_code_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_metadata_code_low
+end interface
+
+interface
+   integer function trexio_read_metadata_author_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_metadata_author_low
+end interface
+
+interface
+   integer function trexio_read_nucleus_label_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_nucleus_label_low
+end interface
+
+interface
+   integer function trexio_read_mo_class_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_mo_class_low
+end interface
+
+interface
+   integer function trexio_read_mo_symmetry_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(out) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_read_mo_symmetry_low
+end interface
+
+interface
+   integer function trexio_write_metadata_code_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_metadata_code_num_32
+end interface
+
+interface
+   integer function trexio_write_metadata_author_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_metadata_author_num_32
+end interface
+
+interface
+   integer function trexio_write_electron_up_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_electron_up_num_32
+end interface
+
+interface
+   integer function trexio_write_electron_dn_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_electron_dn_num_32
+end interface
+
+interface
+   integer function trexio_write_nucleus_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_nucleus_num_32
+end interface
+
+interface
+   integer function trexio_write_nucleus_repulsion_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in), value :: num
+   end function trexio_write_nucleus_repulsion_32
+end interface
+
+interface
+   integer function trexio_write_ecp_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_ecp_num_32
+end interface
+
+interface
+   integer function trexio_write_basis_prim_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_basis_prim_num_32
+end interface
+
+interface
+   integer function trexio_write_basis_shell_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_basis_shell_num_32
+end interface
+
+interface
+   integer function trexio_write_ao_cartesian_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_ao_cartesian_32
+end interface
+
+interface
+   integer function trexio_write_ao_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_ao_num_32
+end interface
+
+interface
+   integer function trexio_write_mo_num_32 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_mo_num_32
+end interface
+
+interface
+   integer function trexio_write_metadata_code_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_metadata_code_num_64
+end interface
+
+interface
+   integer function trexio_write_metadata_author_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_metadata_author_num_64
+end interface
+
+interface
+   integer function trexio_write_electron_up_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_electron_up_num_64
+end interface
+
+interface
+   integer function trexio_write_electron_dn_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_electron_dn_num_64
+end interface
+
+interface
+   integer function trexio_write_nucleus_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_nucleus_num_64
+end interface
+
+interface
+   integer function trexio_write_nucleus_repulsion_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in), value :: num
+   end function trexio_write_nucleus_repulsion_64
+end interface
+
+interface
+   integer function trexio_write_ecp_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_ecp_num_64
+end interface
+
+interface
+   integer function trexio_write_basis_prim_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_basis_prim_num_64
+end interface
+
+interface
+   integer function trexio_write_basis_shell_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_basis_shell_num_64
+end interface
+
+interface
+   integer function trexio_write_ao_cartesian_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_ao_cartesian_64
+end interface
+
+interface
+   integer function trexio_write_ao_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_ao_num_64
+end interface
+
+interface
+   integer function trexio_write_mo_num_64 (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: num
+   end function trexio_write_mo_num_64
+end interface
+
+interface
+   integer function trexio_write_metadata_code_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_metadata_code_num
+end interface
+
+interface
+   integer function trexio_write_metadata_author_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_metadata_author_num
+end interface
+
+interface
+   integer function trexio_write_electron_up_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_electron_up_num
+end interface
+
+interface
+   integer function trexio_write_electron_dn_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_electron_dn_num
+end interface
+
+interface
+   integer function trexio_write_nucleus_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_nucleus_num
+end interface
+
+interface
+   integer function trexio_write_nucleus_repulsion (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in), value :: num
+   end function trexio_write_nucleus_repulsion
+end interface
+
+interface
+   integer function trexio_write_ecp_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_ecp_num
+end interface
+
+interface
+   integer function trexio_write_basis_prim_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_basis_prim_num
+end interface
+
+interface
+   integer function trexio_write_basis_shell_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_basis_shell_num
+end interface
+
+interface
+   integer function trexio_write_ao_cartesian (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_ao_cartesian
+end interface
+
+interface
+   integer function trexio_write_ao_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_ao_num
+end interface
+
+interface
+   integer function trexio_write_mo_num (trex_file, num) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in), value :: num
+   end function trexio_write_mo_num
+end interface
+
+interface
+   integer function trexio_write_metadata_package_version_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_write_metadata_package_version")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_metadata_package_version_c
+end interface
+
+interface
+   integer function trexio_write_metadata_description_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_write_metadata_description")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_metadata_description_c
+end interface
+
+interface
+   integer function trexio_write_nucleus_point_group_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_write_nucleus_point_group")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_nucleus_point_group_c
+end interface
+
+interface
+   integer function trexio_write_basis_type_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_write_basis_type")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_basis_type_c
+end interface
+
+interface
+   integer function trexio_write_mo_type_c (trex_file, str, max_str_len) &
+           bind(C, name="trexio_write_mo_type")
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: str(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_mo_type_c
+end interface
+
+interface
+   integer function trexio_write_nucleus_charge_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_nucleus_charge_32
+end interface
+
+interface
+   integer function trexio_write_nucleus_coord_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_nucleus_coord_32
+end interface
+
+interface
+   integer function trexio_write_ecp_max_ang_mom_plus_1_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_max_ang_mom_plus_1_32
+end interface
+
+interface
+   integer function trexio_write_ecp_z_core_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_z_core_32
+end interface
+
+interface
+   integer function trexio_write_ecp_ang_mom_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_ang_mom_32
+end interface
+
+interface
+   integer function trexio_write_ecp_nucleus_index_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_nucleus_index_32
+end interface
+
+interface
+   integer function trexio_write_ecp_exponent_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_exponent_32
+end interface
+
+interface
+   integer function trexio_write_ecp_coefficient_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_coefficient_32
+end interface
+
+interface
+   integer function trexio_write_ecp_power_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_power_32
+end interface
+
+interface
+   integer function trexio_write_basis_nucleus_index_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_basis_nucleus_index_32
+end interface
+
+interface
+   integer function trexio_write_basis_shell_ang_mom_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_basis_shell_ang_mom_32
+end interface
+
+interface
+   integer function trexio_write_basis_shell_factor_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_basis_shell_factor_32
+end interface
+
+interface
+   integer function trexio_write_basis_shell_index_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_basis_shell_index_32
+end interface
+
+interface
+   integer function trexio_write_basis_exponent_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_basis_exponent_32
+end interface
+
+interface
+   integer function trexio_write_basis_coefficient_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_basis_coefficient_32
+end interface
+
+interface
+   integer function trexio_write_basis_prim_factor_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_basis_prim_factor_32
+end interface
+
+interface
+   integer function trexio_write_ao_shell_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ao_shell_32
+end interface
+
+interface
+   integer function trexio_write_ao_normalization_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_ao_normalization_32
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_overlap_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_overlap_32
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_kinetic_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_kinetic_32
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_potential_n_e_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_potential_n_e_32
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_ecp_local_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_ecp_local_32
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_ecp_non_local_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_ecp_non_local_32
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_core_hamiltonian_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_core_hamiltonian_32
+end interface
+
+interface
+   integer function trexio_write_mo_coefficient_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_mo_coefficient_32
+end interface
+
+interface
+   integer function trexio_write_mo_occupation_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_mo_occupation_32
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_overlap_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_overlap_32
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_kinetic_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_kinetic_32
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_potential_n_e_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_potential_n_e_32
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_ecp_local_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_ecp_local_32
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_ecp_non_local_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_ecp_non_local_32
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_core_hamiltonian_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_core_hamiltonian_32
+end interface
+
+interface
+   integer function trexio_write_rdm_1e_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_rdm_1e_32
+end interface
+
+interface
+   integer function trexio_write_rdm_1e_up_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_rdm_1e_up_32
+end interface
+
+interface
+   integer function trexio_write_rdm_1e_dn_32 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(4), intent(in) :: dset(*)
+   end function trexio_write_rdm_1e_dn_32
+end interface
+
+interface
+   integer function trexio_write_nucleus_charge_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_nucleus_charge_64
+end interface
+
+interface
+   integer function trexio_write_nucleus_coord_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_nucleus_coord_64
+end interface
+
+interface
+   integer function trexio_write_ecp_max_ang_mom_plus_1_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in) :: dset(*)
+   end function trexio_write_ecp_max_ang_mom_plus_1_64
+end interface
+
+interface
+   integer function trexio_write_ecp_z_core_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in) :: dset(*)
+   end function trexio_write_ecp_z_core_64
+end interface
+
+interface
+   integer function trexio_write_ecp_ang_mom_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in) :: dset(*)
+   end function trexio_write_ecp_ang_mom_64
+end interface
+
+interface
+   integer function trexio_write_ecp_nucleus_index_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in) :: dset(*)
+   end function trexio_write_ecp_nucleus_index_64
+end interface
+
+interface
+   integer function trexio_write_ecp_exponent_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ecp_exponent_64
+end interface
+
+interface
+   integer function trexio_write_ecp_coefficient_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ecp_coefficient_64
+end interface
+
+interface
+   integer function trexio_write_ecp_power_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in) :: dset(*)
+   end function trexio_write_ecp_power_64
+end interface
+
+interface
+   integer function trexio_write_basis_nucleus_index_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in) :: dset(*)
+   end function trexio_write_basis_nucleus_index_64
+end interface
+
+interface
+   integer function trexio_write_basis_shell_ang_mom_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in) :: dset(*)
+   end function trexio_write_basis_shell_ang_mom_64
+end interface
+
+interface
+   integer function trexio_write_basis_shell_factor_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_basis_shell_factor_64
+end interface
+
+interface
+   integer function trexio_write_basis_shell_index_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in) :: dset(*)
+   end function trexio_write_basis_shell_index_64
+end interface
+
+interface
+   integer function trexio_write_basis_exponent_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_basis_exponent_64
+end interface
+
+interface
+   integer function trexio_write_basis_coefficient_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_basis_coefficient_64
+end interface
+
+interface
+   integer function trexio_write_basis_prim_factor_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_basis_prim_factor_64
+end interface
+
+interface
+   integer function trexio_write_ao_shell_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in) :: dset(*)
+   end function trexio_write_ao_shell_64
+end interface
+
+interface
+   integer function trexio_write_ao_normalization_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_normalization_64
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_overlap_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_overlap_64
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_kinetic_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_kinetic_64
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_potential_n_e_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_potential_n_e_64
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_ecp_local_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_ecp_local_64
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_ecp_non_local_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_ecp_non_local_64
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_core_hamiltonian_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_core_hamiltonian_64
+end interface
+
+interface
+   integer function trexio_write_mo_coefficient_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_coefficient_64
+end interface
+
+interface
+   integer function trexio_write_mo_occupation_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_occupation_64
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_overlap_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_overlap_64
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_kinetic_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_kinetic_64
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_potential_n_e_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_potential_n_e_64
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_ecp_local_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_ecp_local_64
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_ecp_non_local_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_ecp_non_local_64
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_core_hamiltonian_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_core_hamiltonian_64
+end interface
+
+interface
+   integer function trexio_write_rdm_1e_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_rdm_1e_64
+end interface
+
+interface
+   integer function trexio_write_rdm_1e_up_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_rdm_1e_up_64
+end interface
+
+interface
+   integer function trexio_write_rdm_1e_dn_64 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_rdm_1e_dn_64
+end interface
+
+interface
+   integer function trexio_write_nucleus_charge (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_nucleus_charge
+end interface
+
+interface
+   integer function trexio_write_nucleus_coord (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_nucleus_coord
+end interface
+
+interface
+   integer function trexio_write_ecp_max_ang_mom_plus_1 (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_max_ang_mom_plus_1
+end interface
+
+interface
+   integer function trexio_write_ecp_z_core (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_z_core
+end interface
+
+interface
+   integer function trexio_write_ecp_ang_mom (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_ang_mom
+end interface
+
+interface
+   integer function trexio_write_ecp_nucleus_index (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_nucleus_index
+end interface
+
+interface
+   integer function trexio_write_ecp_exponent (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ecp_exponent
+end interface
+
+interface
+   integer function trexio_write_ecp_coefficient (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ecp_coefficient
+end interface
+
+interface
+   integer function trexio_write_ecp_power (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ecp_power
+end interface
+
+interface
+   integer function trexio_write_basis_nucleus_index (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_basis_nucleus_index
+end interface
+
+interface
+   integer function trexio_write_basis_shell_ang_mom (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_basis_shell_ang_mom
+end interface
+
+interface
+   integer function trexio_write_basis_shell_factor (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_basis_shell_factor
+end interface
+
+interface
+   integer function trexio_write_basis_shell_index (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_basis_shell_index
+end interface
+
+interface
+   integer function trexio_write_basis_exponent (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_basis_exponent
+end interface
+
+interface
+   integer function trexio_write_basis_coefficient (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_basis_coefficient
+end interface
+
+interface
+   integer function trexio_write_basis_prim_factor (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_basis_prim_factor
+end interface
+
+interface
+   integer function trexio_write_ao_shell (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(4), intent(in) :: dset(*)
+   end function trexio_write_ao_shell
+end interface
+
+interface
+   integer function trexio_write_ao_normalization (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_normalization
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_overlap (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_overlap
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_kinetic (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_kinetic
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_potential_n_e (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_potential_n_e
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_ecp_local (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_ecp_local
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_ecp_non_local (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_ecp_non_local
+end interface
+
+interface
+   integer function trexio_write_ao_1e_int_core_hamiltonian (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_ao_1e_int_core_hamiltonian
+end interface
+
+interface
+   integer function trexio_write_mo_coefficient (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_coefficient
+end interface
+
+interface
+   integer function trexio_write_mo_occupation (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_occupation
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_overlap (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_overlap
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_kinetic (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_kinetic
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_potential_n_e (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_potential_n_e
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_ecp_local (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_ecp_local
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_ecp_non_local (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_ecp_non_local
+end interface
+
+interface
+   integer function trexio_write_mo_1e_int_core_hamiltonian (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_mo_1e_int_core_hamiltonian
+end interface
+
+interface
+   integer function trexio_write_rdm_1e (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_rdm_1e
+end interface
+
+interface
+   integer function trexio_write_rdm_1e_up (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_rdm_1e_up
+end interface
+
+interface
+   integer function trexio_write_rdm_1e_dn (trex_file, dset) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     real(8), intent(in) :: dset(*)
+   end function trexio_write_rdm_1e_dn
+end interface
+
+interface
+   integer function trexio_write_ao_2e_int_eri (trex_file, &
+                                                      offset_file, buffer_size, &
+                                                      index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(in)  :: value_sparse(*)
+   end function trexio_write_ao_2e_int_eri
+end interface
+
+interface
+   integer function trexio_write_ao_2e_int_eri_lr (trex_file, &
+                                                      offset_file, buffer_size, &
+                                                      index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(in)  :: value_sparse(*)
+   end function trexio_write_ao_2e_int_eri_lr
+end interface
+
+interface
+   integer function trexio_write_mo_2e_int_eri (trex_file, &
+                                                      offset_file, buffer_size, &
+                                                      index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(in)  :: value_sparse(*)
+   end function trexio_write_mo_2e_int_eri
+end interface
+
+interface
+   integer function trexio_write_mo_2e_int_eri_lr (trex_file, &
+                                                      offset_file, buffer_size, &
+                                                      index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(in)  :: value_sparse(*)
+   end function trexio_write_mo_2e_int_eri_lr
+end interface
+
+interface
+   integer function trexio_write_rdm_2e (trex_file, &
+                                                      offset_file, buffer_size, &
+                                                      index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(in)  :: value_sparse(*)
+   end function trexio_write_rdm_2e
+end interface
+
+interface
+   integer function trexio_write_rdm_2e_upup (trex_file, &
+                                                      offset_file, buffer_size, &
+                                                      index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(in)  :: value_sparse(*)
+   end function trexio_write_rdm_2e_upup
+end interface
+
+interface
+   integer function trexio_write_rdm_2e_dndn (trex_file, &
+                                                      offset_file, buffer_size, &
+                                                      index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(in)  :: value_sparse(*)
+   end function trexio_write_rdm_2e_dndn
+end interface
+
+interface
+   integer function trexio_write_rdm_2e_updn (trex_file, &
+                                                      offset_file, buffer_size, &
+                                                      index_sparse, value_sparse) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     integer(8), intent(in), value :: offset_file
+     integer(8), intent(in), value :: buffer_size
+     integer(4), intent(in)        :: index_sparse(*)
+     double precision, intent(in)  :: value_sparse(*)
+   end function trexio_write_rdm_2e_updn
+end interface
+
+interface
+   integer function trexio_write_metadata_code_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_metadata_code_low
+end interface
+
+interface
+   integer function trexio_write_metadata_author_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_metadata_author_low
+end interface
+
+interface
+   integer function trexio_write_nucleus_label_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_nucleus_label_low
+end interface
+
+interface
+   integer function trexio_write_mo_class_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_mo_class_low
+end interface
+
+interface
+   integer function trexio_write_mo_symmetry_low (trex_file, dset, max_str_len) bind(C)
+     use, intrinsic :: iso_c_binding
+     integer(8), intent(in), value :: trex_file
+     character, intent(in) :: dset(*)
+     integer(4), intent(in), value :: max_str_len
+   end function trexio_write_mo_symmetry_low
+end interface
+
+contains
+   integer(8) function trexio_open (filename, mode, backend, rc_open)
+     use, intrinsic :: iso_c_binding, only : c_null_char
+     implicit none
+     character(len=*), intent(in)                 :: filename
+     character, intent(in), value                 :: mode
+     integer(trexio_backend), intent(in), value   :: backend
+     integer(trexio_exit_code), intent(out)       :: rc_open
+     character(len=len_trim(filename)+1) :: filename_c
+     integer(trexio_exit_code) :: rc
+
+     filename_c = trim(filename) // c_null_char
+     trexio_open = trexio_open_c(filename_c, mode, backend, rc_open)
+     if (trexio_open == 0_8 .or. rc_open /= TREXIO_SUCCESS) then
+       return
+     endif
+     rc = trexio_set_one_based(trexio_open)
+     if (rc /= TREXIO_SUCCESS) then
+        rc = trexio_close(trexio_open)
+        trexio_open = 0_8
+     endif
+   end function trexio_open
+
+subroutine trexio_strarray2str(str_array, max_num_str, max_len_str, str_res)
+  use, intrinsic :: iso_c_binding, only : c_null_char
+  implicit none
+
+  integer(8), intent(in), value   :: max_num_str  ! number of elements in strign array
+  integer, intent(in), value   :: max_len_str  ! maximum length of a string in an array
+  character(len=*), intent(in)  :: str_array(*)
+  character(len=:), allocatable, intent(out) :: str_res
+  integer :: i
+
+  str_res = ''
+  do i = 1, max_num_str
+    str_res = str_res // trim(str_array(i)) // TREXIO_DELIM
+  enddo
+  str_res = str_res // c_null_char
+
+end subroutine trexio_strarray2str
+
+subroutine trexio_str2strarray(str_flat, max_num_str, max_len_str, str_array)
+  implicit none
+
+  integer(8), intent(in), value   :: max_num_str  ! number of elements in strign array
+  integer, intent(in), value   :: max_len_str  ! maximum length of a string in an array
+  character, intent(in) :: str_flat(*)
+  character(len=*), intent(inout)  :: str_array(*)
+
+  character(len=max_len_str)  :: tmp_str
+  integer :: i, j, k, ind, offset
+  integer(8) :: len_flat
+
+  len_flat = (max_len_str+1)*max_num_str + 1
+
+  ind=1
+  offset=1
+  do i=1,max_num_str
+    k = 1
+    tmp_str=''
+    do j=ind,len_flat
+      if (str_flat(j) == TREXIO_DELIM) then
+        ind=j+1
+        exit
+      endif
+      tmp_str(k:k) = str_flat(j)
+      k = k + 1
+    enddo
+    str_array(i)=tmp_str
+    offset=ind
+  enddo
+
+end subroutine trexio_str2strarray
+
+subroutine trexio_assert(trexio_rc, check_rc, success_message)
+  implicit none
+
+  integer, intent(in), value   :: trexio_rc
+  integer, intent(in), value   :: check_rc
+  character(len=*), intent(in), optional  :: success_message
+
+  character*(128) :: str
+
+  if (trexio_rc == check_rc) then
+    if (present(success_message)) write(*,*) success_message
+  else
+    call trexio_string_of_error(trexio_rc, str)
+    print *, trim(str)
+    call exit(1)
+  endif
+
+end subroutine trexio_assert
+integer function trexio_read_metadata_package_version (trex_file, str, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character, intent(out) :: str(*)
+
+  trexio_read_metadata_package_version = trexio_read_metadata_package_version_c(trex_file, str, max_str_len)
+
+end function trexio_read_metadata_package_version
+
+integer function trexio_read_metadata_description (trex_file, str, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character, intent(out) :: str(*)
+
+  trexio_read_metadata_description = trexio_read_metadata_description_c(trex_file, str, max_str_len)
+
+end function trexio_read_metadata_description
+
+integer function trexio_read_nucleus_point_group (trex_file, str, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character, intent(out) :: str(*)
+
+  trexio_read_nucleus_point_group = trexio_read_nucleus_point_group_c(trex_file, str, max_str_len)
+
+end function trexio_read_nucleus_point_group
+
+integer function trexio_read_basis_type (trex_file, str, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character, intent(out) :: str(*)
+
+  trexio_read_basis_type = trexio_read_basis_type_c(trex_file, str, max_str_len)
+
+end function trexio_read_basis_type
+
+integer function trexio_read_mo_type (trex_file, str, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character, intent(out) :: str(*)
+
+  trexio_read_mo_type = trexio_read_mo_type_c(trex_file, str, max_str_len)
+
+end function trexio_read_mo_type
+
+integer function trexio_read_metadata_code (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(inout) :: dset(*)
+
+  character, allocatable :: str_compiled(:)
+  integer(8) :: metadata_code_num
+  integer :: rc
+
+  rc = trexio_read_metadata_code_num_64(trex_file, metadata_code_num)
+  if (rc /= TREXIO_SUCCESS) trexio_read_metadata_code = rc
+
+  allocate(str_compiled(metadata_code_num*(max_str_len+1)+1))
+
+  rc = trexio_read_metadata_code_low(trex_file, str_compiled, max_str_len)
+  if (rc /= TREXIO_SUCCESS) then
+    deallocate(str_compiled)
+    trexio_read_metadata_code = rc
+  else
+    call trexio_str2strarray(str_compiled, metadata_code_num, max_str_len, dset)
+    deallocate(str_compiled)
+    trexio_read_metadata_code = TREXIO_SUCCESS
+  endif
+
+end function trexio_read_metadata_code
+
+integer function trexio_read_metadata_author (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(inout) :: dset(*)
+
+  character, allocatable :: str_compiled(:)
+  integer(8) :: metadata_author_num
+  integer :: rc
+
+  rc = trexio_read_metadata_author_num_64(trex_file, metadata_author_num)
+  if (rc /= TREXIO_SUCCESS) trexio_read_metadata_author = rc
+
+  allocate(str_compiled(metadata_author_num*(max_str_len+1)+1))
+
+  rc = trexio_read_metadata_author_low(trex_file, str_compiled, max_str_len)
+  if (rc /= TREXIO_SUCCESS) then
+    deallocate(str_compiled)
+    trexio_read_metadata_author = rc
+  else
+    call trexio_str2strarray(str_compiled, metadata_author_num, max_str_len, dset)
+    deallocate(str_compiled)
+    trexio_read_metadata_author = TREXIO_SUCCESS
+  endif
+
+end function trexio_read_metadata_author
+
+integer function trexio_read_nucleus_label (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(inout) :: dset(*)
+
+  character, allocatable :: str_compiled(:)
+  integer(8) :: nucleus_num
+  integer :: rc
+
+  rc = trexio_read_nucleus_num_64(trex_file, nucleus_num)
+  if (rc /= TREXIO_SUCCESS) trexio_read_nucleus_label = rc
+
+  allocate(str_compiled(nucleus_num*(max_str_len+1)+1))
+
+  rc = trexio_read_nucleus_label_low(trex_file, str_compiled, max_str_len)
+  if (rc /= TREXIO_SUCCESS) then
+    deallocate(str_compiled)
+    trexio_read_nucleus_label = rc
+  else
+    call trexio_str2strarray(str_compiled, nucleus_num, max_str_len, dset)
+    deallocate(str_compiled)
+    trexio_read_nucleus_label = TREXIO_SUCCESS
+  endif
+
+end function trexio_read_nucleus_label
+
+integer function trexio_read_mo_class (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(inout) :: dset(*)
+
+  character, allocatable :: str_compiled(:)
+  integer(8) :: mo_num
+  integer :: rc
+
+  rc = trexio_read_mo_num_64(trex_file, mo_num)
+  if (rc /= TREXIO_SUCCESS) trexio_read_mo_class = rc
+
+  allocate(str_compiled(mo_num*(max_str_len+1)+1))
+
+  rc = trexio_read_mo_class_low(trex_file, str_compiled, max_str_len)
+  if (rc /= TREXIO_SUCCESS) then
+    deallocate(str_compiled)
+    trexio_read_mo_class = rc
+  else
+    call trexio_str2strarray(str_compiled, mo_num, max_str_len, dset)
+    deallocate(str_compiled)
+    trexio_read_mo_class = TREXIO_SUCCESS
+  endif
+
+end function trexio_read_mo_class
+
+integer function trexio_read_mo_symmetry (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(inout) :: dset(*)
+
+  character, allocatable :: str_compiled(:)
+  integer(8) :: mo_num
+  integer :: rc
+
+  rc = trexio_read_mo_num_64(trex_file, mo_num)
+  if (rc /= TREXIO_SUCCESS) trexio_read_mo_symmetry = rc
+
+  allocate(str_compiled(mo_num*(max_str_len+1)+1))
+
+  rc = trexio_read_mo_symmetry_low(trex_file, str_compiled, max_str_len)
+  if (rc /= TREXIO_SUCCESS) then
+    deallocate(str_compiled)
+    trexio_read_mo_symmetry = rc
+  else
+    call trexio_str2strarray(str_compiled, mo_num, max_str_len, dset)
+    deallocate(str_compiled)
+    trexio_read_mo_symmetry = TREXIO_SUCCESS
+  endif
+
+end function trexio_read_mo_symmetry
+
+integer function trexio_write_metadata_package_version (trex_file, str, max_str_len)
+  use, intrinsic :: iso_c_binding, only : c_null_char
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: str
+
+  character(len=len_trim(str)+1) :: str_c
+
+  str_c = trim(str) // c_null_char
+
+  trexio_write_metadata_package_version = trexio_write_metadata_package_version_c(trex_file, str_c, max_str_len)
+
+end function trexio_write_metadata_package_version
+
+integer function trexio_write_metadata_description (trex_file, str, max_str_len)
+  use, intrinsic :: iso_c_binding, only : c_null_char
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: str
+
+  character(len=len_trim(str)+1) :: str_c
+
+  str_c = trim(str) // c_null_char
+
+  trexio_write_metadata_description = trexio_write_metadata_description_c(trex_file, str_c, max_str_len)
+
+end function trexio_write_metadata_description
+
+integer function trexio_write_nucleus_point_group (trex_file, str, max_str_len)
+  use, intrinsic :: iso_c_binding, only : c_null_char
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: str
+
+  character(len=len_trim(str)+1) :: str_c
+
+  str_c = trim(str) // c_null_char
+
+  trexio_write_nucleus_point_group = trexio_write_nucleus_point_group_c(trex_file, str_c, max_str_len)
+
+end function trexio_write_nucleus_point_group
+
+integer function trexio_write_basis_type (trex_file, str, max_str_len)
+  use, intrinsic :: iso_c_binding, only : c_null_char
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: str
+
+  character(len=len_trim(str)+1) :: str_c
+
+  str_c = trim(str) // c_null_char
+
+  trexio_write_basis_type = trexio_write_basis_type_c(trex_file, str_c, max_str_len)
+
+end function trexio_write_basis_type
+
+integer function trexio_write_mo_type (trex_file, str, max_str_len)
+  use, intrinsic :: iso_c_binding, only : c_null_char
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: str
+
+  character(len=len_trim(str)+1) :: str_c
+
+  str_c = trim(str) // c_null_char
+
+  trexio_write_mo_type = trexio_write_mo_type_c(trex_file, str_c, max_str_len)
+
+end function trexio_write_mo_type
+
+integer function trexio_write_metadata_code (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: dset(*)
+
+  character(len=:), allocatable :: str_compiled
+  integer(8) :: metadata_code_num
+  integer :: rc
+
+  rc = trexio_read_metadata_code_num_64(trex_file, metadata_code_num)
+  if (rc /= TREXIO_SUCCESS) then
+    trexio_write_metadata_code = rc
+  else
+    call trexio_strarray2str(dset, metadata_code_num, max_str_len, str_compiled)
+    trexio_write_metadata_code = trexio_write_metadata_code_low(trex_file, str_compiled, max_str_len)
+  endif
+
+end function trexio_write_metadata_code
+
+integer function trexio_write_metadata_author (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: dset(*)
+
+  character(len=:), allocatable :: str_compiled
+  integer(8) :: metadata_author_num
+  integer :: rc
+
+  rc = trexio_read_metadata_author_num_64(trex_file, metadata_author_num)
+  if (rc /= TREXIO_SUCCESS) then
+    trexio_write_metadata_author = rc
+  else
+    call trexio_strarray2str(dset, metadata_author_num, max_str_len, str_compiled)
+    trexio_write_metadata_author = trexio_write_metadata_author_low(trex_file, str_compiled, max_str_len)
+  endif
+
+end function trexio_write_metadata_author
+
+integer function trexio_write_nucleus_label (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: dset(*)
+
+  character(len=:), allocatable :: str_compiled
+  integer(8) :: nucleus_num
+  integer :: rc
+
+  rc = trexio_read_nucleus_num_64(trex_file, nucleus_num)
+  if (rc /= TREXIO_SUCCESS) then
+    trexio_write_nucleus_label = rc
+  else
+    call trexio_strarray2str(dset, nucleus_num, max_str_len, str_compiled)
+    trexio_write_nucleus_label = trexio_write_nucleus_label_low(trex_file, str_compiled, max_str_len)
+  endif
+
+end function trexio_write_nucleus_label
+
+integer function trexio_write_mo_class (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: dset(*)
+
+  character(len=:), allocatable :: str_compiled
+  integer(8) :: mo_num
+  integer :: rc
+
+  rc = trexio_read_mo_num_64(trex_file, mo_num)
+  if (rc /= TREXIO_SUCCESS) then
+    trexio_write_mo_class = rc
+  else
+    call trexio_strarray2str(dset, mo_num, max_str_len, str_compiled)
+    trexio_write_mo_class = trexio_write_mo_class_low(trex_file, str_compiled, max_str_len)
+  endif
+
+end function trexio_write_mo_class
+
+integer function trexio_write_mo_symmetry (trex_file, dset, max_str_len)
+  implicit none
+  integer(8), intent(in), value :: trex_file
+  integer(4), intent(in), value :: max_str_len
+  character(len=*), intent(in) :: dset(*)
+
+  character(len=:), allocatable :: str_compiled
+  integer(8) :: mo_num
+  integer :: rc
+
+  rc = trexio_read_mo_num_64(trex_file, mo_num)
+  if (rc /= TREXIO_SUCCESS) then
+    trexio_write_mo_symmetry = rc
+  else
+    call trexio_strarray2str(dset, mo_num, max_str_len, str_compiled)
+    trexio_write_mo_symmetry = trexio_write_mo_symmetry_low(trex_file, str_compiled, max_str_len)
+  endif
+
+end function trexio_write_mo_symmetry
+
+end module trexio
diff --git a/stable/champ/NEED b/stable/champ/NEED
index e4a8008..19fd652 100644
--- a/stable/champ/NEED
+++ b/stable/champ/NEED
@@ -1 +1 @@
-determinants fci
+determinants fci csf
diff --git a/stable/champ/save_for_champ.irp.f b/stable/champ/save_for_champ.irp.f
index 7e88e71..3268b4e 100644
--- a/stable/champ/save_for_champ.irp.f
+++ b/stable/champ/save_for_champ.irp.f
@@ -1,4 +1,4 @@
-program qmcpack
+program save_for_camp
   implicit none
   BEGIN_DOC
 ! Generates a file for CHAMP
@@ -23,6 +23,7 @@ program qmcpack
   call system('rm '//trim(ezfio_filename)//'/mo_basis/ao_md5')
   call system('$QP_ROOT/src/champ/qp_convert.py '//trim(ezfio_filename))
 
+  call write_champ_csf()
 !  integer :: iunit
 !  integer, external :: getUnitAndOpen
 !  iunit = getUnitAndOpen(trim(ezfio_filename)//'.H','w')
diff --git a/stable/champ/write_champ_csf.irp.f b/stable/champ/write_champ_csf.irp.f
new file mode 100644
index 0000000..eddd20a
--- /dev/null
+++ b/stable/champ/write_champ_csf.irp.f
@@ -0,0 +1,99 @@
+subroutine write_champ_csf
+  implicit none
+
+  integer, parameter             :: istate=1
+  character*(2048)               :: format
+  integer                        :: i, n_elements, j, k
+  integer, allocatable           :: list(:,:)
+
+  integer                        :: startdet, enddet, iunit
+  integer                        :: ndetI, bfIcfg, s
+  double precision               :: phasedet
+  integer                        :: idx
+
+  open(newunit=iunit, file='det.'//ezfio_filename)
+
+  write(iunit, '(A, X, I4,  X, A, X, I4)') '&electrons nelec', elec_num, 'nup', elec_alpha_num
+
+
+  ! Determinants
+  write(iunit, '(A, I10)') 'determinants', N_det
+
+  write(format,*) '(', N_det, '(F12.8, X))'
+  write(iunit, format) psi_coef(1:N_det,istate)
+
+  write(format,*) '( ', elec_alpha_num, '(I4,X), 2X, ', elec_beta_num, '(I4,X))'
+  allocate ( list(bit_kind_size,2) )
+  do i=1, N_det
+   call bitstring_to_list( psi_det(1,1,i), list(1,1), n_elements, N_int)
+   call bitstring_to_list( psi_det(1,2,i), list(1,2), n_elements, N_int)
+   write(iunit,format) list(1:elec_alpha_num,1), list(1:elec_beta_num,2)
+  end do
+  write(iunit, '(A)') 'end'
+
+  ! CSF
+  write(iunit, '(A, I10, X, I3)') 'csf', N_csf, N_states
+
+  write(format,*) '(', N_csf, '(F12.8, X))'
+  do i=1,N_states
+    write(iunit, format) psi_csf_coef(1:N_csf,i)
+  end do
+
+  write(iunit, '(A)') 'end'
+
+  ! CSF map
+  phasedet = 1.0d0
+
+  ndetI = 0
+  do i=1,N_configuration
+    startdet = psi_configuration_to_psi_det(1,i)
+    enddet = psi_configuration_to_psi_det(2,i)
+    s = 0
+    do k=1,N_int
+      if (psi_configuration(k,1,i) == 0_bit_kind) cycle
+      s = s + popcnt(psi_configuration(k,1,i))
+    enddo
+    bfIcfg = max(1,nint((binom(s,(s+1)/2)-binom(s,((s+1)/2)+1))))
+    do k=1,bfIcfg
+      do j = startdet, enddet
+        if (DetToCSFTransformationMatrix(s,k,j-startdet+1) == 0.d0) cycle
+        ndetI += 1
+      end do
+    end do
+  end do
+
+  write(iunit, '(A)') 'csfmap'
+  write(iunit, '(I10, I10, I10)') n_csf, n_det, ndetI
+
+  do i=1,N_configuration
+    startdet = psi_configuration_to_psi_det(1,i)
+    enddet = psi_configuration_to_psi_det(2,i)
+
+    s = 0
+    do k=1,N_int
+      if (psi_configuration(k,1,i) == 0_bit_kind) cycle
+      s = s + popcnt(psi_configuration(k,1,i))
+    enddo
+    bfIcfg = max(1,nint((binom(s,(s+1)/2)-binom(s,((s+1)/2)+1))))
+
+    do k=1,bfIcfg
+      ndetI = 0
+      do j = startdet, enddet
+        if (DetToCSFTransformationMatrix(s,k,j-startdet+1) == 0.d0) cycle
+        ndetI += 1
+      end do
+
+      write(iunit, '(I4)') ndetI
+      do j = startdet, enddet
+        if (DetToCSFTransformationMatrix(s,k,j-startdet+1) == 0.d0) cycle
+        idx = psi_configuration_to_psi_det_data(j)
+        call get_phase_qp_to_cfg(psi_det(1,1,idx), psi_det(1,2,idx), phasedet)
+        write(iunit, '(I10, F18.12)') idx, DetToCSFTransformationMatrix(s,k,j-startdet+1)*phasedet
+      end do
+    end do
+
+  end do
+
+  write(iunit, '(A)') 'end'
+
+end
diff --git a/stable/utilities/truncate_wf.irp.f b/stable/utilities/truncate_wf.irp.f
index f1904d5..6c66c8e 100644
--- a/stable/utilities/truncate_wf.irp.f
+++ b/stable/utilities/truncate_wf.irp.f
@@ -59,7 +59,7 @@ subroutine routine_s2
  do i=1,N_det
    print *,  i, real(weight_configuration(det_to_configuration(i),:)), real(sum(weight_configuration(det_to_configuration(i),:)))
  enddo
- print*, 'Min weight of the occupation pattern ?'
+ print*, 'Min weight of the configuration?'
  read(5,*) wmin
 
  ndet_max = 0