diff --git a/src/pytrexio.i b/src/pytrexio.i
index a2ba005..52a7be9 100644
--- a/src/pytrexio.i
+++ b/src/pytrexio.i
@@ -43,7 +43,7 @@
 /* Return number of sparse data points stored in the file as part of the output tuple */
 %apply int *OUTPUT { int64_t* const size_max};
 /* Return number of sparse data points read from the file as part of the output tuple */
-/* %apply int *INOUT { int64_t* const buffer_size_read}; */
+%apply int *INOUT { int64_t* const buffer_size_read};
 
 /* Does not work for arrays (SIGSEGV) */
 
@@ -88,11 +88,11 @@ import_array();
 %apply (int64_t* ARGOUT_ARRAY1, int64_t DIM1) {(int64_t* const dset_out, const int64_t dim_out)};
 %apply (int64_t* IN_ARRAY1, int64_t DIM1) {(const int64_t* dset_in, const int64_t dim_in)};
 /* Enable write|read_safe functions to convert numpy arrays from/to sparse arrays */
-%apply (double* IN_ARRAY1, int64_t DIM1) {(const double* value_sparse, const int64_t size_value_write)};
-%apply (int32_t* IN_ARRAY1, int64_t DIM1) {(const int32_t* index_sparse, const int64_t size_index_write)};
+%apply (double* IN_ARRAY1, int64_t DIM1) {(const double* value_sparse_write, const int64_t size_value_write)};
+%apply (int32_t* IN_ARRAY1, int64_t DIM1) {(const int32_t* index_sparse_write, const int64_t size_index_write)};
 
-%apply (int32_t* ARGOUT_ARRAY1, int DIM1) {(int32_t* const index_sparse_read, const int64_t size_index_read)};
-%apply (double* ARGOUT_ARRAY1, int DIM1) {(double* const value_sparse_read, const int64_t size_value_read)};
+%apply (double* ARGOUT_ARRAY1, int64_t DIM1) {(double* const value_sparse_read, const int64_t size_value_read)};
+%apply (int32_t* ARGOUT_ARRAY1, int64_t DIM1) {(int32_t* const index_sparse_read, const int64_t size_index_read)};
 
 /* This tells SWIG to treat char ** dset_in pattern as a special case
    Enables access to trexio_[...]_write_dset_str set of functions directly, i.e.
diff --git a/src/templates_front/templator_front.org b/src/templates_front/templator_front.org
index 874c36a..bb7f661 100644
--- a/src/templates_front/templator_front.org
+++ b/src/templates_front/templator_front.org
@@ -2416,11 +2416,25 @@ 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, 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);
+trexio_exit_code trexio_read_safe_$group_dset$(trexio_t* const file, const int64_t offset_file, int64_t* const buffer_size_read, int32_t* const index_sparse_read, const int64_t size_index_read, double* const value_sparse_read, const int64_t size_value_read);
+trexio_exit_code trexio_write_safe_$group_dset$(trexio_t* const file, const int64_t offset_file, const int64_t buffer_size, const int32_t* index_sparse_write, const int64_t size_index_write, const double* value_sparse_write, const int64_t size_value_write);
      #+end_src
 
 **** Source code for default functions
 
   #+begin_src c :tangle read_dset_sparse_front.c
+trexio_exit_code trexio_read_safe_$group_dset$(trexio_t* const file,
+                                               const int64_t offset_file,
+                                               int64_t* const buffer_size_read,
+                                               int32_t* const index_sparse_read,
+                                               const int64_t size_index_read,
+                                               double* const value_sparse_read,
+                                               const int64_t size_value_read
+                                               )
+{
+  return trexio_read_$group_dset$(file, offset_file, buffer_size_read, index_sparse_read, value_sparse_read);
+}
+
 trexio_exit_code
 trexio_read_$group_dset$(trexio_t* const file,
                          const int64_t offset_file,
@@ -2525,13 +2539,25 @@ trexio_read_$group_dset$_size(trexio_t* const file, int64_t* const size_max)
 
 
   #+begin_src c :tangle write_dset_sparse_front.c
+trexio_exit_code trexio_write_safe_$group_dset$(trexio_t* const file,
+                                                const int64_t offset_file,
+                                                const int64_t buffer_size,
+                                                const int32_t* index_sparse_write,
+                                                const int64_t size_index_write,
+                                                const double* value_sparse_write,
+                                                const int64_t size_value_write
+                                                )
+{
+  return trexio_write_$group_dset$(file, offset_file, buffer_size, index_sparse_write, value_sparse_write);
+}
+
 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
-                           )
+                          const int64_t offset_file,
+                          const int64_t buffer_size,
+                          const int32_t* index_sparse,
+                          const double* value_sparse
+                          )
 {
   if (file  == NULL) return TREXIO_INVALID_ARG_1;
   if (offset_file < 0L) return TREXIO_INVALID_ARG_2;