diff --git a/src/templates_front/templator_front.org b/src/templates_front/templator_front.org
index e7a2d3e..aa98d8c 100644
--- a/src/templates_front/templator_front.org
+++ b/src/templates_front/templator_front.org
@@ -2413,7 +2413,7 @@ def has_$group_dset$(trexio_file) -> bool:
 
      #+begin_src c :tangle hrw_dset_sparse_front.h :exports none
 trexio_exit_code trexio_has_$group_dset$(trexio_t* const file);
-trexio_exit_code trexio_read_$group_dset$(trexio_t* const file, const int64_t offset_file, const int64_t buffer_size, int32_t* const index_sparse, double* const value_sparse);
+trexio_exit_code trexio_read_$group_dset$(trexio_t* const file, const int64_t offset_file, int64_t* const buffer_size, int32_t* const index_sparse, double* const value_sparse);
 trexio_exit_code trexio_read_$group_dset$_size(trexio_t* const file, int64_t* const size_max);
 trexio_exit_code trexio_write_$group_dset$(trexio_t* const file, const int64_t offset_file, const int64_t buffer_size, const int32_t* index_sparse, const double* value_sparse);
      #+end_src
@@ -2424,14 +2424,14 @@ trexio_exit_code trexio_write_$group_dset$(trexio_t* const file, const int64_t o
 trexio_exit_code
 trexio_read_$group_dset$(trexio_t* const file,
                          const int64_t offset_file,
-                         const int64_t buffer_size,
+                         int64_t* const buffer_size,
                          int32_t* const index_sparse,
                          double* const value_sparse
                          )
 {
   if (file  == NULL) return TREXIO_INVALID_ARG_1;
   if (offset_file < 0L) return TREXIO_INVALID_ARG_2;
-  if (buffer_size <= 0L) return TREXIO_INVALID_ARG_3;
+  if (*buffer_size <= 0L) return TREXIO_INVALID_ARG_3;
   if (index_sparse == NULL) return TREXIO_INVALID_ARG_4;
   if (value_sparse == NULL) return TREXIO_INVALID_ARG_5;
   if (trexio_has_$group_dset$(file) != TREXIO_SUCCESS) return TREXIO_DSET_MISSING;
@@ -2455,12 +2455,12 @@ trexio_read_$group_dset$(trexio_t* const file,
   switch (file->back_end) {
 
   case TREXIO_TEXT:
-    rc = trexio_text_read_$group_dset$(file, offset_file, buffer_size, size_max, &eof_read_size, index_sparse, value_sparse);
+    rc = trexio_text_read_$group_dset$(file, offset_file, *buffer_size, size_max, &eof_read_size, index_sparse, value_sparse);
     break;
 
   case TREXIO_HDF5:
 #ifdef HAVE_HDF5
-    rc = trexio_hdf5_read_$group_dset$(file, offset_file, buffer_size, num, &eof_read_size, index_sparse, value_sparse);
+    rc = trexio_hdf5_read_$group_dset$(file, offset_file, *buffer_size, num, &eof_read_size, index_sparse, value_sparse);
     break;
 #else
     rc = TREXIO_BACK_END_MISSING;
@@ -2476,10 +2476,12 @@ trexio_read_$group_dset$(trexio_t* const file,
 
   if (rc != TREXIO_SUCCESS && rc != TREXIO_END) return rc;
 
+  if (rc == TREXIO_END) *buffer_size = eof_read_size;
+
   // shift indices to be one-based if Fortran API is used
   if (file->one_based) {
     // if EOF is reached - shift only indices that have been read, not an entire buffer
-    uint64_t index_size = (rc == TREXIO_END) ? (rank*eof_read_size) : (rank*buffer_size) ;
+    uint64_t index_size = rank*(*buffer_size) ;
     for (uint64_t i=0; i<index_size; ++i){
       index_sparse[i] += 1;
     }
@@ -2636,8 +2638,8 @@ trexio_has_$group_dset$ (trexio_t* const file)
      #+begin_src f90 :tangle write_dset_sparse_front_fortran.f90
 interface
    integer function trexio_write_$group_dset$ (trex_file, &
-                                                      offset_file, buffer_size, &
-                                                      index_sparse, value_sparse) bind(C)
+                                               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
@@ -2651,13 +2653,13 @@ end interface
      #+begin_src f90 :tangle read_dset_sparse_front_fortran.f90
 interface
    integer function trexio_read_$group_dset$ (trex_file, &
-                                                     offset_file, buffer_size, &
-                                                     index_sparse, value_sparse) bind(C)
+                                              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(*)
+     integer(8), intent(out)       :: buffer_size
+     integer(4), intent(out)       :: index_sparse(*)
      double precision, intent(out) :: value_sparse(*)
    end function trexio_read_$group_dset$
 end interface
@@ -2666,7 +2668,7 @@ end interface
      #+begin_src f90 :tangle read_dset_sparse_size_front_fortran.f90
 interface
    integer function trexio_read_$group_dset$_size (trex_file, &
-                                                          size_max) bind(C)
+                                                   size_max) bind(C)
      use, intrinsic :: iso_c_binding
      integer(8), intent(in), value :: trex_file
      integer(8), intent(out) :: size_max
diff --git a/tests/io_dset_sparse_hdf5.c b/tests/io_dset_sparse_hdf5.c
index 67e3f09..67b8357 100644
--- a/tests/io_dset_sparse_hdf5.c
+++ b/tests/io_dset_sparse_hdf5.c
@@ -134,26 +134,36 @@ static int test_read_dset_sparse (const char* file_name, const back_end_t backen
   int64_t chunk_read = 10L;
   int64_t offset_file_read = 40L;
   int offset_data_read = 5;
+  int64_t read_size_check;
+  read_size_check = chunk_read;
 
   if (offset != 0L) offset_file_read += offset;
 
   // read one chunk using the aforementioned parameters
-  rc = trexio_read_mo_2e_int_eri(file, offset_file_read, chunk_read, &index_read[4*offset_data_read], &value_read[offset_data_read]);
+  rc = trexio_read_mo_2e_int_eri(file, offset_file_read, &chunk_read, &index_read[4*offset_data_read], &value_read[offset_data_read]);
   assert(rc == TREXIO_SUCCESS);
+  assert(chunk_read == read_size_check);
   assert(index_read[0] == 0);
   assert(index_read[4*offset_data_read] == 4 * (int32_t) (offset_file_read-offset));
 
   // now attempt to read so that one encounters end of file during reading (i.e. offset_file_read + chunk_read > size_max)
-  offset_file_read = 97L;
+  offset_file_read = 97;
   offset_data_read = 1;
+  int64_t eof_read_size_check = SIZE - offset_file_read; // if offset_file_read=97 => only 3 integrals will be read out of total of 100
 
   if (offset != 0L) offset_file_read += offset;
 
   // read one chunk that will reach EOF and return TREXIO_END code
-  rc = trexio_read_mo_2e_int_eri(file, offset_file_read, chunk_read, &index_read[4*offset_data_read], &value_read[offset_data_read]);
+  rc = trexio_read_mo_2e_int_eri(file, offset_file_read, &chunk_read, &index_read[4*offset_data_read], &value_read[offset_data_read]);
   assert(rc == TREXIO_END);
+  assert(chunk_read == eof_read_size_check);
   assert(index_read[4*size_r-1] == 0);
   assert(index_read[4*offset_data_read] == 4 * (int32_t) (offset_file_read-offset));
+  /*
+  for(int i=0; i<size_r; ++i){
+    printf("%d %lf\n", index_read[4*i], value_read[i]);
+  }
+  */
 
   // close current session
   rc = trexio_close(file);
diff --git a/tests/io_dset_sparse_text.c b/tests/io_dset_sparse_text.c
index c08a335..52b0c8a 100644
--- a/tests/io_dset_sparse_text.c
+++ b/tests/io_dset_sparse_text.c
@@ -134,24 +134,29 @@ static int test_read_dset_sparse (const char* file_name, const back_end_t backen
   int64_t chunk_read = 10L;
   int64_t offset_file_read = 40L;
   int offset_data_read = 5;
+  int64_t read_size_check;
+  read_size_check = chunk_read;
 
   if (offset != 0L) offset_file_read += offset;
 
   // read one chunk using the aforementioned parameters
-  rc = trexio_read_mo_2e_int_eri(file, offset_file_read, chunk_read, &index_read[4*offset_data_read], &value_read[offset_data_read]);
+  rc = trexio_read_mo_2e_int_eri(file, offset_file_read, &chunk_read, &index_read[4*offset_data_read], &value_read[offset_data_read]);
   assert(rc == TREXIO_SUCCESS);
+  assert(chunk_read == read_size_check);
   assert(index_read[0] == 0);
   assert(index_read[4*offset_data_read] == 4 * (int32_t) (offset_file_read-offset));
 
   // now attempt to read so that one encounters end of file during reading (i.e. offset_file_read + chunk_read > size_max)
   offset_file_read = 97L;
   offset_data_read = 1;
+  int64_t eof_read_size_check = SIZE - offset_file_read; // if offset_file_read=97 => only 3 integrals will be read out of total of 100
 
   if (offset != 0L) offset_file_read += offset;
 
   // read one chunk that will reach EOF and return TREXIO_END code
-  rc = trexio_read_mo_2e_int_eri(file, offset_file_read, chunk_read, &index_read[4*offset_data_read], &value_read[offset_data_read]);
+  rc = trexio_read_mo_2e_int_eri(file, offset_file_read, &chunk_read, &index_read[4*offset_data_read], &value_read[offset_data_read]);
   assert(rc == TREXIO_END);
+  assert(chunk_read == eof_read_size_check);
   assert(index_read[4*size_r-1] == 0);
   assert(index_read[4*offset_data_read] == 4 * (int32_t) (offset_file_read-offset));
 
diff --git a/tests/test_f.f90 b/tests/test_f.f90
index 01fc89a..dcadec8 100644
--- a/tests/test_f.f90
+++ b/tests/test_f.f90
@@ -200,6 +200,7 @@ subroutine test_read(file_name, back_end)
   integer(4) :: index_sparse_mo_2e_int_eri(4,20)
   double precision :: value_sparse_mo_2e_int_eri(20)
   integer(8) :: read_buf_size = 10
+  integer(8) :: read_buf_size_save = 10
   integer(8) :: offset_read = 40
   integer(8) :: offset_data_read = 5
   integer(8) :: offset_eof  = 97
@@ -282,6 +283,9 @@ subroutine test_read(file_name, back_end)
   rc = trexio_read_mo_2e_int_eri(trex_file, offset_read, read_buf_size, &
 	                         index_sparse_mo_2e_int_eri(1, offset_data_read + 1), &
 			         value_sparse_mo_2e_int_eri(offset_data_read + 1))
+  !do  i = 1,20
+  !  write(*,*) index_sparse_mo_2e_int_eri(1,i)
+  !enddo
   call trexio_assert(rc, TREXIO_SUCCESS)
   if (index_sparse_mo_2e_int_eri(1, 1) == 0 .and. &
       index_sparse_mo_2e_int_eri(1, offset_data_read + 1) == offset_read*4 + 1) then
@@ -297,14 +301,16 @@ subroutine test_read(file_name, back_end)
   rc = trexio_read_mo_2e_int_eri(trex_file, offset_eof, read_buf_size, &
 	                         index_sparse_mo_2e_int_eri(1, offset_data_eof + 1), &
 			         value_sparse_mo_2e_int_eri(offset_data_eof + 1))
-  call trexio_assert(rc, TREXIO_END)
   !do  i = 1,20
   !  write(*,*) index_sparse_mo_2e_int_eri(1,i)
   !enddo
-  if (index_sparse_mo_2e_int_eri(1, 1) == 0 .and. &
+  call trexio_assert(rc, TREXIO_END)
+  if (read_buf_size == 3 .and. &
+      index_sparse_mo_2e_int_eri(1, 1) == 0 .and. &
       index_sparse_mo_2e_int_eri(1, offset_data_read + 1) == offset_read*4 + 1 .and. &
       index_sparse_mo_2e_int_eri(1, offset_data_eof + 1) == offset_eof*4 + 1) then
     write(*,*) 'SUCCESS READ SPARSE DATA EOF'
+    read_buf_size = read_buf_size_save
   else
     print *, 'FAILURE SPARSE DATA EOF CHECK'
     call exit(-1)