diff --git a/parallel-rdp-standalone/glguts.c b/parallel-rdp-standalone/glguts.c
index a38a40b..2ff47bc 100644
--- a/parallel-rdp-standalone/glguts.c
+++ b/parallel-rdp-standalone/glguts.c
@@ -57,7 +57,7 @@ int32_t window_width;
 int32_t window_height;
 int32_t window_fullscreen;
 int32_t window_widescreen;
-bool window_vsync;
+int32_t window_vsync;
 
 #define SHADER_HEADER "#version 330 core\n"
 #define TEX_FORMAT GL_RGBA
diff --git a/parallel-rdp-standalone/glguts.h b/parallel-rdp-standalone/glguts.h
index 957fd87..a06ff8a 100644
--- a/parallel-rdp-standalone/glguts.h
+++ b/parallel-rdp-standalone/glguts.h
@@ -39,7 +39,7 @@ extern "C"
     extern int32_t window_height;
     extern int32_t window_fullscreen;
     extern int32_t window_widescreen;
-    extern bool window_vsync;
+    extern int32_t window_vsync;
 
 #ifdef __cplusplus
 }