diff --git a/basis/opengl/gl/extensions/extensions-tests.factor b/basis/opengl/gl/extensions/extensions-tests.factor
new file mode 100644
index 0000000000..4e87d9da86
--- /dev/null
+++ b/basis/opengl/gl/extensions/extensions-tests.factor
@@ -0,0 +1,7 @@
+USING: alien kernel opengl.gl.extensions system tools.test ;
+IN: opengl.gl.extensions.tests
+
+{ t } [
+    gl-function-calling-convention
+    os windows? [ stdcall ] [ cdecl ] if =
+] unit-test
diff --git a/basis/opengl/gl/extensions/extensions.factor b/basis/opengl/gl/extensions/extensions.factor
index 7944ed1455..4fbf78bac2 100644
--- a/basis/opengl/gl/extensions/extensions.factor
+++ b/basis/opengl/gl/extensions/extensions.factor
@@ -46,6 +46,9 @@ reset-gl-function-number-counter
     names return function-effect
     define-declared ;
 
+: gl-function-calling-convention ( -- symbol )
+    os windows? [ stdcall ] [ cdecl ] if ;
+
 SYNTAX: GL-FUNCTION:
     gl-function-calling-convention
     scan-function-name
diff --git a/basis/opengl/gl/gtk/gtk.factor b/basis/opengl/gl/gtk/gtk.factor
index c5fbdeebb3..850f60edc4 100644
--- a/basis/opengl/gl/gtk/gtk.factor
+++ b/basis/opengl/gl/gtk/gtk.factor
@@ -9,5 +9,3 @@ IN: opengl.gl.gtk
 
 : gl-function-address ( name -- address )
     ascii string>alien gdk_gl_get_proc_address ; inline
-
-: gl-function-calling-convention ( -- str ) cdecl ; inline
diff --git a/basis/opengl/gl/macosx/macosx.factor b/basis/opengl/gl/macosx/macosx.factor
index aeaa5da4eb..56696c6bac 100644
--- a/basis/opengl/gl/macosx/macosx.factor
+++ b/basis/opengl/gl/macosx/macosx.factor
@@ -3,4 +3,3 @@ IN: opengl.gl.macosx
 
 : gl-function-context ( -- context ) 0 ; inline
 : gl-function-address ( name -- address ) f dlsym ; inline
-: gl-function-calling-convention ( -- str ) cdecl ; inline
diff --git a/basis/opengl/gl/windows/windows.factor b/basis/opengl/gl/windows/windows.factor
index ba3f102652..f27d20815d 100644
--- a/basis/opengl/gl/windows/windows.factor
+++ b/basis/opengl/gl/windows/windows.factor
@@ -8,4 +8,3 @@ FUNCTION: void* wglGetProcAddress ( c-string name )
 
 : gl-function-context ( -- context ) wglGetCurrentContext ; inline
 : gl-function-address ( name -- address ) wglGetProcAddress ; inline
-: gl-function-calling-convention ( -- str ) stdcall ; inline
diff --git a/basis/opengl/gl/x11/x11.factor b/basis/opengl/gl/x11/x11.factor
index 2d752757bb..f96cc9901a 100644
--- a/basis/opengl/gl/x11/x11.factor
+++ b/basis/opengl/gl/x11/x11.factor
@@ -3,4 +3,3 @@ IN: opengl.gl.x11
 
 : gl-function-context ( -- context ) glXGetCurrentContext ; inline
 : gl-function-address ( name -- address ) glXGetProcAddressARB ; inline
-: gl-function-calling-convention ( -- str ) cdecl ; inline