Nicer output for negative error numbers in strerror_r

1 files changed, 11 insertions, 3 deletions

diff --git a/string/_strerror.c b/string/_strerror.c
index cb5d9e3609..ad9b148108 100644
--- a/string/_strerror.c
+++ b/string/_strerror.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991,93,95,96,97,98,2000,2002,2006
+/* Copyright (C) 1991,93,95,96,97,98,2000,2002,2006,2011
    Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -18,7 +18,9 @@
    02111-1307 USA.  */
 
 #include <libintl.h>
+#include <stdbool.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/param.h>
 #include <stdio-common/_itoa.h>
@@ -43,15 +45,21 @@ __strerror_r (int errnum, char *buf, size_t buflen)
 	 `int' of 8 bytes we never need more than 20 digits.  */
       char numbuf[21];
       const char *unk = _("Unknown error ");
-      const size_t unklen = strlen (unk);
+      size_t unklen = strlen (unk);
       char *p, *q;
+      bool negative = errnum < 0;
 
       numbuf[20] = '\0';
-      p = _itoa_word (errnum, &numbuf[20], 10, 0);
+      p = _itoa_word (abs (errnum), &numbuf[20], 10, 0);
 
       /* Now construct the result while taking care for the destination
 	 buffer size.  */
       q = __mempcpy (buf, unk, MIN (unklen, buflen));
+      if (negative && unklen < buflen)
+	{
+	  *q++ = '-';
+	  ++unklen;
+	}
       if (unklen < buflen)
 	memcpy (q, p, MIN ((size_t) (&numbuf[21] - p), buflen - unklen));