diff --git a/common/rfb/ScaledPixelBuffer.cxx b/common/rfb/ScaledPixelBuffer.cxx
index 056e5d6..dc6096d 100644
--- a/common/rfb/ScaledPixelBuffer.cxx
+++ b/common/rfb/ScaledPixelBuffer.cxx
@@ -75,7 +75,7 @@
 }
 
 void ScaledPixelBuffer::setSourceBuffer(U8 **src_data_, int w, int h) {
-  if (w > 0 && h > 0 && src_data != NULL) {
+  if (w > 0 && h > 0 && src_data_ != NULL) {
     freeWeightTabs();
     src_data = src_data_;
     src_width  = w;