diff --git a/glfw/cocoa_monitor.m b/glfw/cocoa_monitor.m
index 19193b73a..042ac8b7e 100644
--- a/glfw/cocoa_monitor.m
+++ b/glfw/cocoa_monitor.m
@@ -326,7 +326,7 @@ static CVReturn displayLinkCallback(
         const CVTimeStamp* now UNUSED, const CVTimeStamp* outputTime UNUSED,
         CVOptionFlags flagsIn UNUSED, CVOptionFlags* flagsOut UNUSED, void* userInfo)
 {
-    CGDirectDisplayID displayID = (CGDirectDisplayID)userInfo;
+    CGDirectDisplayID displayID = (uintptr_t)userInfo;
     NSNumber *arg = [NSNumber numberWithUnsignedInt:displayID];
     [NSApp performSelectorOnMainThread:@selector(render_frame_received:) withObject:arg waitUntilDone:NO];
     [arg release];