diff --git a/ChangeLog b/ChangeLog
index fef21d943..5fcb7592c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2005-07-20  Carl Worth  <cworth@cworth.org>
+
+	reviewed by: keithp
+
+	* src/cairo.h (CAIRO_CONTENT_VALID): Fix macro to not consider
+	CAIRO_FORMAT_ARGB32 (==0) as a valid cairo_content_t.
+
 2005-07-20  Keith Packard  <keithp@keithp.com>
 
 	reviewed by: otaylor
diff --git a/src/cairo.h b/src/cairo.h
index 41ae83ce7..d1bdc36bb 100644
--- a/src/cairo.h
+++ b/src/cairo.h
@@ -907,9 +907,11 @@ typedef enum _cairo_content {
     CAIRO_CONTENT_COLOR_ALPHA	= 0x3000
 } cairo_content_t;
 
-#define CAIRO_CONTENT_VALID(content) (((content) & ~(CAIRO_CONTENT_COLOR | \
-						     CAIRO_CONTENT_ALPHA | \
-						     CAIRO_CONTENT_COLOR_ALPHA)) == 0)
+#define CAIRO_CONTENT_VALID(content) ((content) && 			         \
+				      (((content) & ~(CAIRO_CONTENT_COLOR |      \
+						      CAIRO_CONTENT_ALPHA |      \
+						      CAIRO_CONTENT_COLOR_ALPHA))\
+				       == 0))
 
 cairo_surface_t *
 cairo_surface_create_similar (cairo_surface_t  *other,