diff --git a/ChangeLog b/ChangeLog
index 690b39cc9..b8c547d2c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2010-11-19  Robert Larice
+ * src/frontend/plotting/clip.c :
+    Nr 1/5 (x = ...) == 0 , swallow warnings
+
 2010-11-16  Robert Larice
  * src/**/* :
     rename `IGNORE()' --> `NG_IGNORE()'
diff --git a/src/frontend/plotting/clip.c b/src/frontend/plotting/clip.c
index 6e90e6106..e92014560 100644
--- a/src/frontend/plotting/clip.c
+++ b/src/frontend/plotting/clip.c
@@ -56,7 +56,7 @@ clip_line(int *pX1, int *pY1, int *pX2, int *pY2, int l, int b, int r, int t)
     while (c1 || c2) {
         if (c1 & c2)
             return (TRUE); /* Line is invisible. */
-        if (!(c = c1))
+        if ((c = c1) == 0)
             c = c2;
         if (c & CODEMINX) {
             y = y1+(y2-y1)*(l-x1)/(x2-x1);