diff --git a/unix/common/RandrGlue.h b/unix/common/RandrGlue.h
index 48ce327..43c9b68 100644
--- a/unix/common/RandrGlue.h
+++ b/unix/common/RandrGlue.h
@@ -51,7 +51,7 @@
                               int width, int height);
 
 unsigned int vncRandRGetOutputId(int outputIdx);
-void vncRandRGetOutputDimensions(int outputIdx,
+int vncRandRGetOutputDimensions(int outputIdx,
                                  int *x, int *y, int *width, int *height);
 
 int vncRandRCreateOutputs(int extraOutputs);