1 files changed, 3 insertions, 0 deletions
diff --git a/src/dmx.c b/src/dmx.c
index 1df28e6..5df1068 100644
--- a/src/dmx.c
+++ b/src/dmx.c
@@ -407,6 +407,9 @@ Bool DMXAddScreen(Display *dpy, const char *displayName, unsigned int mask,
     int                length;
     int                paddedLength;
 
+    if (!screen)
+	return False;
+
     DMXCheckExtension(dpy, info, False);
 
     LockDisplay(dpy);