diff --git a/c_code/interface_triangle.c b/c_code/interface_triangle.c
index 63618ad..e25607d 100644
--- a/c_code/interface_triangle.c
+++ b/c_code/interface_triangle.c
@@ -486,7 +486,7 @@ int32_t tri_out_voronoi_npoint(struct ExtTrigen *trigen) {
     return trigen->voronoi.numberofpoints;
 }
 
-int32_t tri_out_voronoi_point(struct ExtTrigen *trigen, int32_t index, int32_t dim) {
+double tri_out_voronoi_point(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 02a9eeb..9613c2c 100644
--- a/c_code/interface_triangle.h
+++ b/c_code/interface_triangle.h
@@ -57,7 +57,7 @@ int32_t tri_out_cell_attribute(struct ExtTrigen *trigen, int32_t index);
 
 int32_t tri_out_voronoi_npoint(struct ExtTrigen *trigen);
 
-int32_t tri_out_voronoi_point(struct ExtTrigen *trigen, int32_t index, int32_t dim);
+double tri_out_voronoi_point(struct ExtTrigen *trigen, int32_t index, int32_t dim);
 
 int32_t tri_out_voronoi_nedge(struct ExtTrigen *trigen);