diff --git a/c_code/interface_tetgen.cpp b/c_code/interface_tetgen.cpp
index 4c200ba..cc97af5 100644
--- a/c_code/interface_tetgen.cpp
+++ b/c_code/interface_tetgen.cpp
@@ -18,7 +18,7 @@ void tet_drop_tetgen(struct ExtTetgen *tetgen) {
     delete tetgen;
 }
 
-struct ExtTetgen *tet_new_tetgen(int npoint, int nfacet, int const *facet_npoint, int nregion, int nhole) {
+struct ExtTetgen *tet_new_tetgen(int32_t npoint, int32_t nfacet, int32_t const *facet_npoint, int32_t nregion, int32_t nhole) {
     if (npoint < 4) {
         return NULL;
     }
@@ -46,7 +46,7 @@ struct ExtTetgen *tet_new_tetgen(int npoint, int nfacet, int const *facet_npoint
     }
 
     // point markers
-    tetgen->input.pointmarkerlist = new (std::nothrow) int[npoint];
+    tetgen->input.pointmarkerlist = new (std::nothrow) int32_t[npoint];
     if (tetgen->input.pointmarkerlist == NULL) {
         tet_drop_tetgen(tetgen);
         return NULL;
@@ -60,9 +60,9 @@ struct ExtTetgen *tet_new_tetgen(int npoint, int nfacet, int const *facet_npoint
             tet_drop_tetgen(tetgen);
             return NULL;
         }
-        tetgen->input.facetmarkerlist = new (std::nothrow) int[nfacet];
-        const int NUM_POLY = 1;
-        for (int index = 0; index < nfacet; index++) {
+        tetgen->input.facetmarkerlist = new (std::nothrow) int32_t[nfacet];
+        const int32_t NUM_POLY = 1;
+        for (int32_t index = 0; index < nfacet; index++) {
             // facet polygon
             tetgenio::facet *fac = &tetgen->input.facetlist[index];
             fac->polygonlist = new (std::nothrow) tetgenio::polygon[NUM_POLY];
@@ -76,7 +76,7 @@ struct ExtTetgen *tet_new_tetgen(int npoint, int nfacet, int const *facet_npoint
             // facet polygon vertices
             size_t nvertex = facet_npoint[index];
             tetgenio::polygon *gon = &fac->polygonlist[0];
-            gon->vertexlist = new (std::nothrow) int[nvertex];
+            gon->vertexlist = new (std::nothrow) int32_t[nvertex];
             if (gon->vertexlist == NULL) {
                 tet_drop_tetgen(tetgen);
                 return NULL;
@@ -110,7 +110,7 @@ struct ExtTetgen *tet_new_tetgen(int npoint, int nfacet, int const *facet_npoint
     return tetgen;
 }
 
-int tet_set_point(struct ExtTetgen *tetgen, int index, int marker, double x, double y, double z) {
+int32_t tet_set_point(struct ExtTetgen *tetgen, int32_t index, int32_t marker, double x, double y, double z) {
     if (tetgen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -128,7 +128,7 @@ int tet_set_point(struct ExtTetgen *tetgen, int index, int marker, double x, dou
     return TRITET_SUCCESS;
 }
 
-int tet_set_facet_point(struct ExtTetgen *tetgen, int index, int m, int p) {
+int32_t tet_set_facet_point(struct ExtTetgen *tetgen, int32_t index, int32_t m, int32_t p) {
     if (tetgen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -159,7 +159,7 @@ int tet_set_facet_point(struct ExtTetgen *tetgen, int index, int m, int p) {
     return TRITET_SUCCESS;
 }
 
-int tet_set_facet_marker(struct ExtTetgen *tetgen, int index, int marker) {
+int32_t tet_set_facet_marker(struct ExtTetgen *tetgen, int32_t index, int32_t marker) {
     if (tetgen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -175,7 +175,7 @@ int tet_set_facet_marker(struct ExtTetgen *tetgen, int index, int marker) {
     return TRITET_SUCCESS;
 }
 
-int tet_set_region(struct ExtTetgen *tetgen, int index, int attribute, double x, double y, double z, double max_volume) {
+int32_t tet_set_region(struct ExtTetgen *tetgen, int32_t index, int32_t attribute, double x, double y, double z, double max_volume) {
     if (tetgen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -194,7 +194,7 @@ int tet_set_region(struct ExtTetgen *tetgen, int index, int attribute, double x,
     return TRITET_SUCCESS;
 }
 
-int tet_set_hole(struct ExtTetgen *tetgen, int index, double x, double y, double z) {
+int32_t tet_set_hole(struct ExtTetgen *tetgen, int32_t index, double x, double y, double z) {
     if (tetgen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -211,7 +211,7 @@ int tet_set_hole(struct ExtTetgen *tetgen, int index, double x, double y, double
     return TRITET_SUCCESS;
 }
 
-int tet_run_delaunay(struct ExtTetgen *tetgen, int verbose) {
+int32_t tet_run_delaunay(struct ExtTetgen *tetgen, int32_t verbose) {
     if (tetgen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -229,7 +229,7 @@ int tet_run_delaunay(struct ExtTetgen *tetgen, int verbose) {
     }
     try {
         tetrahedralize(command, &tetgen->input, &tetgen->output, NULL, NULL);
-    } catch (int status) {
+    } catch (int32_t status) {
         printf("status = %d\n", status); // TODO
     } catch (...) {
         return 1; // TODO
@@ -238,7 +238,7 @@ int tet_run_delaunay(struct ExtTetgen *tetgen, int verbose) {
     return TRITET_SUCCESS;
 }
 
-int tet_run_tetrahedralize(struct ExtTetgen *tetgen, int verbose, int o2, double global_max_volume, double global_min_angle) {
+int32_t tet_run_tetrahedralize(struct ExtTetgen *tetgen, int32_t verbose, int32_t o2, double global_max_volume, double global_min_angle) {
     if (tetgen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -301,7 +301,7 @@ int tet_run_tetrahedralize(struct ExtTetgen *tetgen, int verbose, int o2, double
     }
     if (global_max_volume > 0.0) {
         char buf[32];
-        int n = snprintf(buf, 32, "a%.15f", global_max_volume);
+        int32_t n = snprintf(buf, 32, "a%.15f", global_max_volume);
         if (n >= 32) {
             return TRITET_ERROR_STRING_CONCAT;
         }
@@ -309,7 +309,7 @@ int tet_run_tetrahedralize(struct ExtTetgen *tetgen, int verbose, int o2, double
     }
     if (global_min_angle > 0.0) {
         char buf[32];
-        int n = snprintf(buf, 32, "q%.15f", global_min_angle);
+        int32_t n = snprintf(buf, 32, "q%.15f", global_min_angle);
         if (n >= 32) {
             return TRITET_ERROR_STRING_CONCAT;
         }
@@ -319,7 +319,7 @@ int tet_run_tetrahedralize(struct ExtTetgen *tetgen, int verbose, int o2, double
     }
     try {
         tetrahedralize(command, &tetgen->input, &tetgen->output, NULL, NULL);
-    } catch (int status) {
+    } catch (int32_t status) {
         printf("status = %d\n", status); // TODO
     } catch (...) {
         return 1; // TODO
@@ -328,28 +328,28 @@ int tet_run_tetrahedralize(struct ExtTetgen *tetgen, int verbose, int o2, double
     return TRITET_SUCCESS;
 }
 
-int tet_out_npoint(struct ExtTetgen *tetgen) {
+int32_t tet_out_npoint(struct ExtTetgen *tetgen) {
     if (tetgen == NULL) {
         return 0;
     }
     return tetgen->output.numberofpoints;
 }
 
-int tet_out_ncell(struct ExtTetgen *tetgen) {
+int32_t tet_out_ncell(struct ExtTetgen *tetgen) {
     if (tetgen == NULL) {
         return 0;
     }
     return tetgen->output.numberoftetrahedra;
 }
 
-int tet_out_cell_npoint(struct ExtTetgen *tetgen) {
+int32_t tet_out_cell_npoint(struct ExtTetgen *tetgen) {
     if (tetgen == NULL) {
         return 0;
     }
     return tetgen->output.numberofcorners;
 }
 
-double tet_out_point(struct ExtTetgen *tetgen, int index, int dim) {
+double tet_out_point(struct ExtTetgen *tetgen, int32_t index, int32_t dim) {
     if (tetgen == NULL) {
         return 0.0;
     }
@@ -360,7 +360,7 @@ double tet_out_point(struct ExtTetgen *tetgen, int index, int dim) {
     }
 }
 
-int tet_out_point_marker(struct ExtTetgen *tetgen, int index) {
+int32_t tet_out_point_marker(struct ExtTetgen *tetgen, int32_t index) {
     if (tetgen == NULL) {
         return 0;
     }
@@ -371,7 +371,7 @@ int tet_out_point_marker(struct ExtTetgen *tetgen, int index) {
     }
 }
 
-int tet_out_cell_point(struct ExtTetgen *tetgen, int index, int corner) {
+int32_t tet_out_cell_point(struct ExtTetgen *tetgen, int32_t index, int32_t corner) {
     if (tetgen == NULL) {
         return 0;
     }
@@ -382,7 +382,7 @@ int tet_out_cell_point(struct ExtTetgen *tetgen, int index, int corner) {
     }
 }
 
-int tet_out_cell_attribute(struct ExtTetgen *tetgen, int index) {
+int32_t tet_out_cell_attribute(struct ExtTetgen *tetgen, int32_t index) {
     if (tetgen == NULL) {
         return 0;
     }
@@ -393,14 +393,14 @@ int tet_out_cell_attribute(struct ExtTetgen *tetgen, int index) {
     }
 }
 
-int tet_out_n_marked_face(struct ExtTetgen *tetgen) {
+int32_t tet_out_n_marked_face(struct ExtTetgen *tetgen) {
     if (tetgen == NULL) {
         return 0;
     }
     return static_cast<int>(tetgen->output.marked_faces.size());
 }
 
-void tet_out_marked_face(struct ExtTetgen *tetgen, int index, int *a, int *b, int *c, int *marker, int *cell) {
+void tet_out_marked_face(struct ExtTetgen *tetgen, int32_t index, int32_t *a, int32_t *b, int32_t *c, int32_t *marker, int32_t *cell) {
     *a = 0;
     *b = 0;
     *c = 0;
diff --git a/c_code/interface_tetgen.h b/c_code/interface_tetgen.h
index 336e9cc..1266a5c 100644
--- a/c_code/interface_tetgen.h
+++ b/c_code/interface_tetgen.h
@@ -1,6 +1,8 @@
 #ifndef INTERFACE_TETGEN_H
 #define INTERFACE_TETGEN_H
 
+#include <inttypes.h>
+
 #include "tetgen.h"
 
 struct ExtTetgen {
@@ -8,40 +10,40 @@ struct ExtTetgen {
     struct tetgenio output;
 };
 
-struct ExtTetgen *tet_new_tetgen(int npoint, int nfacet, int const *facet_npoint, int nregion, int nhole);
+struct ExtTetgen *tet_new_tetgen(int32_t npoint, int32_t nfacet, int32_t const *facet_npoint, int32_t nregion, int32_t nhole);
 
 void tet_drop_tetgen(struct ExtTetgen *tetgen);
 
-int tet_set_point(struct ExtTetgen *tetgen, int index, int marker, double x, double y, double z);
+int32_t tet_set_point(struct ExtTetgen *tetgen, int32_t index, int32_t marker, double x, double y, double z);
 
-int tet_set_facet_point(struct ExtTetgen *tetgen, int index, int m, int p);
+int32_t tet_set_facet_point(struct ExtTetgen *tetgen, int32_t index, int32_t m, int32_t p);
 
-int tet_set_facet_marker(struct ExtTetgen *tetgen, int index, int marker);
+int32_t tet_set_facet_marker(struct ExtTetgen *tetgen, int32_t index, int32_t marker);
 
-int tet_set_region(struct ExtTetgen *tetgen, int index, int attribute, double x, double y, double z, double max_volume);
+int32_t tet_set_region(struct ExtTetgen *tetgen, int32_t index, int32_t attribute, double x, double y, double z, double max_volume);
 
-int tet_set_hole(struct ExtTetgen *tetgen, int index, double x, double y, double z);
+int32_t tet_set_hole(struct ExtTetgen *tetgen, int32_t index, double x, double y, double z);
 
-int tet_run_delaunay(struct ExtTetgen *tetgen, int verbose);
+int32_t tet_run_delaunay(struct ExtTetgen *tetgen, int32_t verbose);
 
-int tet_run_tetrahedralize(struct ExtTetgen *tetgen, int verbose, int o2, double global_max_volume, double global_min_angle);
+int32_t tet_run_tetrahedralize(struct ExtTetgen *tetgen, int32_t verbose, int32_t o2, double global_max_volume, double global_min_angle);
 
-int tet_out_npoint(struct ExtTetgen *tetgen);
+int32_t tet_out_npoint(struct ExtTetgen *tetgen);
 
-int tet_out_ncell(struct ExtTetgen *tetgen); // a "cell" here is a "tetrahedron"
+int32_t tet_out_ncell(struct ExtTetgen *tetgen); // a "cell" here is a "tetrahedron"
 
-int tet_out_cell_npoint(struct ExtTetgen *tetgen);
+int32_t tet_out_cell_npoint(struct ExtTetgen *tetgen);
 
-double tet_out_point(struct ExtTetgen *tetgen, int index, int dim);
+double tet_out_point(struct ExtTetgen *tetgen, int32_t index, int32_t dim);
 
-int tet_out_point_marker(struct ExtTetgen *tetgen, int index);
+int32_t tet_out_point_marker(struct ExtTetgen *tetgen, int32_t index);
 
-int tet_out_cell_point(struct ExtTetgen *tetgen, int index, int corner);
+int32_t tet_out_cell_point(struct ExtTetgen *tetgen, int32_t index, int32_t corner);
 
-int tet_out_cell_attribute(struct ExtTetgen *tetgen, int index);
+int32_t tet_out_cell_attribute(struct ExtTetgen *tetgen, int32_t index);
 
-int tet_out_n_marked_face(struct ExtTetgen *tetgen);
+int32_t tet_out_n_marked_face(struct ExtTetgen *tetgen);
 
-void tet_out_marked_face(struct ExtTetgen *tetgen, int index, int *a, int *b, int *c, int *marker, int *cell);
+void tet_out_marked_face(struct ExtTetgen *tetgen, int32_t index, int32_t *a, int32_t *b, int32_t *c, int32_t *marker, int32_t *cell);
 
 #endif // INTERFACE_TETGEN_H
\ No newline at end of file
diff --git a/c_code/interface_triangle.c b/c_code/interface_triangle.c
index cb0b0f6..63618ad 100644
--- a/c_code/interface_triangle.c
+++ b/c_code/interface_triangle.c
@@ -111,7 +111,7 @@ void free_triangle_data(struct triangulateio *data) {
     zero_triangle_data(data);
 }
 
-struct ExtTrigen *tri_new_trigen(int npoint, int nsegment, int nregion, int nhole) {
+struct ExtTrigen *tri_new_trigen(int32_t npoint, int32_t nsegment, int32_t nregion, int32_t nhole) {
     if (npoint < 3) {
         return NULL;
     }
@@ -134,7 +134,7 @@ struct ExtTrigen *tri_new_trigen(int npoint, int nsegment, int nregion, int nhol
     trigen->input.numberofpoints = npoint;
 
     // point markers
-    trigen->input.pointmarkerlist = (int *)malloc(npoint * sizeof(int));
+    trigen->input.pointmarkerlist = (int32_t *)malloc(npoint * sizeof(int32_t));
     if (trigen->input.pointmarkerlist == NULL) {
         free(trigen);
         return NULL;
@@ -142,13 +142,13 @@ struct ExtTrigen *tri_new_trigen(int npoint, int nsegment, int nregion, int nhol
 
     // segments
     if (nsegment > 0) {
-        trigen->input.segmentlist = (int *)malloc(nsegment * 2 * sizeof(int));
+        trigen->input.segmentlist = (int32_t *)malloc(nsegment * 2 * sizeof(int32_t));
         if (trigen->input.segmentlist == NULL) {
             free_triangle_data(&trigen->input);
             free(trigen);
             return NULL;
         }
-        trigen->input.segmentmarkerlist = (int *)malloc(nsegment * sizeof(int));
+        trigen->input.segmentmarkerlist = (int32_t *)malloc(nsegment * sizeof(int32_t));
         if (trigen->input.segmentmarkerlist == NULL) {
             free_triangle_data(&trigen->input);
             free(trigen);
@@ -192,7 +192,7 @@ void tri_drop_trigen(struct ExtTrigen *trigen) {
     free(trigen);
 }
 
-int tri_set_point(struct ExtTrigen *trigen, int index, int marker, double x, double y) {
+int32_t tri_set_point(struct ExtTrigen *trigen, int32_t index, int32_t marker, double x, double y) {
     if (trigen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -208,7 +208,7 @@ int tri_set_point(struct ExtTrigen *trigen, int index, int marker, double x, dou
     return TRITET_SUCCESS;
 }
 
-int tri_set_segment(struct ExtTrigen *trigen, int index, int marker, int a, int b) {
+int32_t tri_set_segment(struct ExtTrigen *trigen, int32_t index, int32_t marker, int32_t a, int32_t b) {
     if (trigen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -227,7 +227,7 @@ int tri_set_segment(struct ExtTrigen *trigen, int index, int marker, int a, int
     return TRITET_SUCCESS;
 }
 
-int tri_set_region(struct ExtTrigen *trigen, int index, int attribute, double x, double y, double max_area) {
+int32_t tri_set_region(struct ExtTrigen *trigen, int32_t index, int32_t attribute, double x, double y, double max_area) {
     // Shewchuk: If you are using the -A and -a switches simultaneously and wish to assign an attribute
     // to some region without imposing an area constraint, use a negative maximum area.
     if (trigen == NULL) {
@@ -246,7 +246,7 @@ int tri_set_region(struct ExtTrigen *trigen, int index, int attribute, double x,
     return TRITET_SUCCESS;
 }
 
-int tri_set_hole(struct ExtTrigen *trigen, int index, double x, double y) {
+int32_t tri_set_hole(struct ExtTrigen *trigen, int32_t index, double x, double y) {
     if (trigen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -261,7 +261,7 @@ int tri_set_hole(struct ExtTrigen *trigen, int index, double x, double y) {
     return TRITET_SUCCESS;
 }
 
-int tri_run_delaunay(struct ExtTrigen *trigen, int verbose) {
+int32_t tri_run_delaunay(struct ExtTrigen *trigen, int32_t verbose) {
     if (trigen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -291,7 +291,7 @@ int tri_run_delaunay(struct ExtTrigen *trigen, int verbose) {
     return TRITET_SUCCESS;
 }
 
-int tri_run_voronoi(struct ExtTrigen *trigen, int verbose) {
+int32_t tri_run_voronoi(struct ExtTrigen *trigen, int32_t verbose) {
     if (trigen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -322,7 +322,7 @@ int tri_run_voronoi(struct ExtTrigen *trigen, int verbose) {
     return TRITET_SUCCESS;
 }
 
-int tri_run_triangulate(struct ExtTrigen *trigen, int verbose, int quadratic, int allow_new_points_on_bry, double global_max_area, double global_min_angle) {
+int32_t tri_run_triangulate(struct ExtTrigen *trigen, int32_t verbose, int32_t quadratic, int32_t allow_new_points_on_bry, double global_max_area, double global_min_angle) {
     if (trigen == NULL) {
         return TRITET_ERROR_NULL_DATA;
     }
@@ -355,7 +355,7 @@ int tri_run_triangulate(struct ExtTrigen *trigen, int verbose, int quadratic, in
     }
     if (global_max_area > 0.0) {
         char buf[32];
-        int n = snprintf(buf, 32, "a%.15f", global_max_area);
+        int32_t n = snprintf(buf, 32, "a%.15f", global_max_area);
         if (n >= 32) {
             return TRITET_ERROR_STRING_CONCAT;
         }
@@ -363,7 +363,7 @@ int tri_run_triangulate(struct ExtTrigen *trigen, int verbose, int quadratic, in
     }
     if (global_min_angle > 0.0) {
         char buf[32];
-        int n = snprintf(buf, 32, "q%.15f", global_min_angle);
+        int32_t n = snprintf(buf, 32, "q%.15f", global_min_angle);
         if (n >= 32) {
             return TRITET_ERROR_STRING_CONCAT;
         }
@@ -385,35 +385,35 @@ int tri_run_triangulate(struct ExtTrigen *trigen, int verbose, int quadratic, in
     return TRITET_SUCCESS;
 }
 
-int tri_out_npoint(struct ExtTrigen *trigen) {
+int32_t tri_out_npoint(struct ExtTrigen *trigen) {
     if (trigen == NULL) {
         return 0;
     }
     return trigen->output.numberofpoints;
 }
 
-int tri_out_nsegment(struct ExtTrigen *trigen) {
+int32_t tri_out_nsegment(struct ExtTrigen *trigen) {
     if (trigen == NULL) {
         return 0;
     }
     return trigen->output.numberofsegments;
 }
 
-int tri_out_ncell(struct ExtTrigen *trigen) {
+int32_t tri_out_ncell(struct ExtTrigen *trigen) {
     if (trigen == NULL) {
         return 0;
     }
     return trigen->output.numberoftriangles;
 }
 
-int tri_out_cell_npoint(struct ExtTrigen *trigen) {
+int32_t tri_out_cell_npoint(struct ExtTrigen *trigen) {
     if (trigen == NULL) {
         return 0;
     }
     return trigen->output.numberofcorners;
 }
 
-double tri_out_point(struct ExtTrigen *trigen, int index, int dim) {
+double tri_out_point(struct ExtTrigen *trigen, int32_t index, int32_t dim) {
     if (trigen == NULL) {
         return 0.0;
     }
@@ -424,7 +424,7 @@ double tri_out_point(struct ExtTrigen *trigen, int index, int dim) {
     }
 }
 
-int tri_out_point_marker(struct ExtTrigen *trigen, int index) {
+int32_t tri_out_point_marker(struct ExtTrigen *trigen, int32_t index) {
     if (trigen == NULL) {
         return 0;
     }
@@ -435,7 +435,7 @@ int tri_out_point_marker(struct ExtTrigen *trigen, int index) {
     }
 }
 
-int tri_out_segment_point(struct ExtTrigen *trigen, int index, int side) {
+int32_t tri_out_segment_point(struct ExtTrigen *trigen, int32_t index, int32_t side) {
     if (trigen == NULL) {
         return 0;
     }
@@ -446,7 +446,7 @@ int tri_out_segment_point(struct ExtTrigen *trigen, int index, int side) {
     }
 }
 
-int tri_out_segment_marker(struct ExtTrigen *trigen, int index) {
+int32_t tri_out_segment_marker(struct ExtTrigen *trigen, int32_t index) {
     if (trigen == NULL) {
         return 0;
     }
@@ -457,7 +457,7 @@ int tri_out_segment_marker(struct ExtTrigen *trigen, int index) {
     }
 }
 
-int tri_out_cell_point(struct ExtTrigen *trigen, int index, int corner) {
+int32_t tri_out_cell_point(struct ExtTrigen *trigen, int32_t index, int32_t corner) {
     if (trigen == NULL) {
         return 0;
     }
@@ -468,7 +468,7 @@ int tri_out_cell_point(struct ExtTrigen *trigen, int index, int corner) {
     }
 }
 
-int tri_out_cell_attribute(struct ExtTrigen *trigen, int index) {
+int32_t tri_out_cell_attribute(struct ExtTrigen *trigen, int32_t index) {
     if (trigen == NULL) {
         return 0;
     }
@@ -479,14 +479,14 @@ int tri_out_cell_attribute(struct ExtTrigen *trigen, int index) {
     }
 }
 
-int tri_out_voronoi_npoint(struct ExtTrigen *trigen) {
+int32_t tri_out_voronoi_npoint(struct ExtTrigen *trigen) {
     if (trigen == NULL) {
         return 0;
     }
     return trigen->voronoi.numberofpoints;
 }
 
-int tri_out_voronoi_point(struct ExtTrigen *trigen, int index, int dim) {
+int32_t tri_out_voronoi_point(struct ExtTrigen *trigen, int32_t index, int32_t dim) {
     if (trigen == NULL) {
         return 0.0;
     }
@@ -497,14 +497,14 @@ int tri_out_voronoi_point(struct ExtTrigen *trigen, int index, int dim) {
     }
 }
 
-int tri_out_voronoi_nedge(struct ExtTrigen *trigen) {
+int32_t tri_out_voronoi_nedge(struct ExtTrigen *trigen) {
     if (trigen == NULL) {
         return 0;
     }
     return trigen->voronoi.numberofedges;
 }
 
-int tri_out_voronoi_edge_point(struct ExtTrigen *trigen, int index, int side) {
+int32_t tri_out_voronoi_edge_point(struct ExtTrigen *trigen, int32_t index, int32_t side) {
     if (trigen == NULL) {
         return 0;
     }
@@ -515,7 +515,7 @@ int tri_out_voronoi_edge_point(struct ExtTrigen *trigen, int index, int side) {
     }
 }
 
-double tri_out_voronoi_edge_point_b_direction(struct ExtTrigen *trigen, int index, int dim) {
+double tri_out_voronoi_edge_point_b_direction(struct ExtTrigen *trigen, int32_t index, int32_t dim) {
     if (trigen == NULL) {
         return 0.0;
     }
diff --git a/c_code/interface_triangle.h b/c_code/interface_triangle.h
index 4bbf2c1..02a9eeb 100644
--- a/c_code/interface_triangle.h
+++ b/c_code/interface_triangle.h
@@ -5,7 +5,7 @@
 
 #define REAL double
 #define ANSI_DECLARATORS
-#define VOID int
+#define VOID int32_t
 #include "triangle.h"
 #undef REAL
 #undef ANSI_DECLARATORS
@@ -17,52 +17,52 @@ struct ExtTrigen {
     struct triangulateio voronoi;
 };
 
-struct ExtTrigen *tri_new_trigen(int npoint, int nsegment, int nregion, int nhole);
+struct ExtTrigen *tri_new_trigen(int32_t npoint, int32_t nsegment, int32_t nregion, int32_t nhole);
 
 void tri_drop_trigen(struct ExtTrigen *trigen);
 
-int tri_set_point(struct ExtTrigen *trigen, int index, int marker, double x, double y);
+int32_t tri_set_point(struct ExtTrigen *trigen, int32_t index, int32_t marker, double x, double y);
 
-int tri_set_segment(struct ExtTrigen *trigen, int index, int marker, int a, int b);
+int32_t tri_set_segment(struct ExtTrigen *trigen, int32_t index, int32_t marker, int32_t a, int32_t b);
 
-int tri_set_region(struct ExtTrigen *trigen, int index, int attribute, double x, double y, double max_area);
+int32_t tri_set_region(struct ExtTrigen *trigen, int32_t index, int32_t attribute, double x, double y, double max_area);
 
-int tri_set_hole(struct ExtTrigen *trigen, int index, double x, double y);
+int32_t tri_set_hole(struct ExtTrigen *trigen, int32_t index, double x, double y);
 
-int tri_run_delaunay(struct ExtTrigen *trigen, int verbose);
+int32_t tri_run_delaunay(struct ExtTrigen *trigen, int32_t verbose);
 
-int tri_run_voronoi(struct ExtTrigen *trigen, int verbose);
+int32_t tri_run_voronoi(struct ExtTrigen *trigen, int32_t verbose);
 
-int tri_run_triangulate(struct ExtTrigen *trigen, int verbose, int quadratic, int allow_new_points_on_bry, double global_max_area, double global_min_angle);
+int32_t tri_run_triangulate(struct ExtTrigen *trigen, int32_t verbose, int32_t quadratic, int32_t allow_new_points_on_bry, double global_max_area, double global_min_angle);
 
-int tri_out_npoint(struct ExtTrigen *trigen);
+int32_t tri_out_npoint(struct ExtTrigen *trigen);
 
-int tri_out_nsegment(struct ExtTrigen *trigen);
+int32_t tri_out_nsegment(struct ExtTrigen *trigen);
 
-int tri_out_ncell(struct ExtTrigen *trigen); // a "cell" here is a "triangle"
+int32_t tri_out_ncell(struct ExtTrigen *trigen); // a "cell" here is a "triangle"
 
-int tri_out_cell_npoint(struct ExtTrigen *trigen);
+int32_t tri_out_cell_npoint(struct ExtTrigen *trigen);
 
-double tri_out_point(struct ExtTrigen *trigen, int index, int dim);
+double tri_out_point(struct ExtTrigen *trigen, int32_t index, int32_t dim);
 
-int tri_out_point_marker(struct ExtTrigen *trigen, int index);
+int32_t tri_out_point_marker(struct ExtTrigen *trigen, int32_t index);
 
-int tri_out_segment_point(struct ExtTrigen *trigen, int index, int side);
+int32_t tri_out_segment_point(struct ExtTrigen *trigen, int32_t index, int32_t side);
 
-int tri_out_segment_marker(struct ExtTrigen *trigen, int index);
+int32_t tri_out_segment_marker(struct ExtTrigen *trigen, int32_t index);
 
-int tri_out_cell_point(struct ExtTrigen *trigen, int index, int corner);
+int32_t tri_out_cell_point(struct ExtTrigen *trigen, int32_t index, int32_t corner);
 
-int tri_out_cell_attribute(struct ExtTrigen *trigen, int index);
+int32_t tri_out_cell_attribute(struct ExtTrigen *trigen, int32_t index);
 
-int tri_out_voronoi_npoint(struct ExtTrigen *trigen);
+int32_t tri_out_voronoi_npoint(struct ExtTrigen *trigen);
 
-int tri_out_voronoi_point(struct ExtTrigen *trigen, int index, int dim);
+int32_t tri_out_voronoi_point(struct ExtTrigen *trigen, int32_t index, int32_t dim);
 
-int tri_out_voronoi_nedge(struct ExtTrigen *trigen);
+int32_t tri_out_voronoi_nedge(struct ExtTrigen *trigen);
 
-int tri_out_voronoi_edge_point(struct ExtTrigen *trigen, int index, int side);
+int32_t tri_out_voronoi_edge_point(struct ExtTrigen *trigen, int32_t index, int32_t side);
 
-double tri_out_voronoi_edge_point_b_direction(struct ExtTrigen *trigen, int index, int dim);
+double tri_out_voronoi_edge_point_b_direction(struct ExtTrigen *trigen, int32_t index, int32_t dim);
 
 #endif // INTERFACE_TRIANGLE_H