Updated to fedora-glibc-20050302T1820

1 files changed, 13 insertions, 4 deletions

diff --git a/string/bits/string3.h b/string/bits/string3.h
index 87cbe35bb1..6c027c23a0 100644
--- a/string/bits/string3.h
+++ b/string/bits/string3.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2004 Free Software Foundation, Inc.
+/* Copyright (C) 2004, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -80,10 +80,19 @@ __mempcpy_ichk (void *__restrict __dest, const void *__restrict __src,
 #endif
 
 
+/* The first two tests here help to catch a somewhat common problem
+   where the second and third parameter are transposed.  This is
+   especially problematic if the intended fill value is zero.  In this
+   case no work is done at all.  We detect these problems by referring
+   non-existing functions.  */
+__warndecl (__warn_memset_zero_len,
+	    "memset used with constant zero length parameter; this could be due to transposed parameters");
 #define memset(dest, ch, len) \
-  ((__bos0 (dest) != (size_t) -1)					\
-   ? __builtin___memset_chk (dest, ch, len, __bos0 (dest))		\
-   : __memset_ichk (dest, ch, len))
+  (__builtin_constant_p (len) && (len) == 0				      \
+   ? (__warn_memset_zero_len (), (void) (ch), (void) (len), (void *) (dest))  \
+   : ((__bos0 (dest) != (size_t) -1)					      \
+      ? __builtin___memset_chk (dest, ch, len, __bos0 (dest))		      \
+      : __memset_ichk (dest, ch, len)))
 static __inline__ void *
 __attribute__ ((__always_inline__))
 __memset_ichk (void *__dest, int __ch, size_t __len)