4 files changed, 12 insertions, 10 deletions
diff --git a/libdimension/gl-stubs.c b/libdimension/gl-stubs.c
index 656b6a8..92fe541 100644
--- a/libdimension/gl-stubs.c
+++ b/libdimension/gl-stubs.c
@@ -29,14 +29,14 @@
 int
 dmnsn_gl_optimize_canvas(dmnsn_canvas *canvas)
 {
-  errno = ENOTSUP;
+  errno = ENOSYS;
   return -1;
 }
 
 int
 dmnsn_gl_write_canvas(const dmnsn_canvas *canvas)
 {
-  errno = ENOTSUP;
+  errno = ENOSYS;
   return -1;
 }
 
@@ -44,6 +44,6 @@ dmnsn_canvas *
 dmnsn_gl_read_canvas(size_t x0, size_t y0,
                      size_t width, size_t height)
 {
-  errno = ENOTSUP;
+  errno = ENOSYS;
   return NULL;
 }
diff --git a/libdimension/png-stubs.c b/libdimension/png-stubs.c
index 04fe608..2696955 100644
--- a/libdimension/png-stubs.c
+++ b/libdimension/png-stubs.c
@@ -29,34 +29,34 @@
 int
 dmnsn_png_optimize_canvas(dmnsn_canvas *canvas)
 {
-  errno = ENOTSUP;
+  errno = ENOSYS;
   return -1;
 }
 
 int
 dmnsn_png_write_canvas(const dmnsn_canvas *canvas, FILE *file)
 {
-  errno = ENOTSUP;
+  errno = ENOSYS;
   return -1;
 }
 
 dmnsn_progress *
 dmnsn_png_write_canvas_async(const dmnsn_canvas *canvas, FILE *file)
 {
-  errno = ENOTSUP;
+  errno = ENOSYS;
   return NULL;
 }
 
 dmnsn_canvas *
 dmnsn_png_read_canvas(FILE *file)
 {
-  errno = ENOTSUP;
+  errno = ENOSYS;
   return NULL;
 }
 
 dmnsn_progress *
 dmnsn_png_read_canvas_async(dmnsn_canvas **canvas, FILE *file)
 {
-  errno = ENOTSUP;
+  errno = ENOSYS;
   return NULL;
 }
diff --git a/tests/libdimension/display-stubs.c b/tests/libdimension/display-stubs.c
index 03cc19d..101289d 100644
--- a/tests/libdimension/display-stubs.c
+++ b/tests/libdimension/display-stubs.c
@@ -18,10 +18,12 @@
  *************************************************************************/
 
 #include "tests.h"
+#include <errno.h>
 
 dmnsn_display *
 dmnsn_new_display(const dmnsn_canvas *canvas)
 {
+  errno = ENOSYS;
   return NULL;
 }
 
diff --git a/tests/libdimension/render.c b/tests/libdimension/render.c
index 776fc1c..136866e 100644
--- a/tests/libdimension/render.c
+++ b/tests/libdimension/render.c
@@ -215,7 +215,7 @@ main(void)
   /* Optimize the canvas for PNG export */
   errno = 0;
   if (dmnsn_png_optimize_canvas(scene->canvas) != 0) {
-    if (errno == ENOTSUP) {
+    if (errno == ENOSYS) {
       have_png = false;
     } else {
       dmnsn_delete_scene(scene);
@@ -227,7 +227,7 @@ main(void)
   /* Optimize the canvas for GL drawing */
   errno = 0;
   if (dmnsn_gl_optimize_canvas(scene->canvas) != 0) {
-    if (errno == ENOTSUP) {
+    if (errno == ENOSYS) {
       have_gl = false;
     } else {
       dmnsn_delete_scene(scene);