fwrite() should also return 0 if either size or nmemb are 0.

Adapted from FreeBSD.  OK deraadt@

1 files changed, 12 insertions, 2 deletions

diff --git a/lib/libc/stdio/fread.3 b/lib/libc/stdio/fread.3
index 972d7b2e996..754636f8d01 100644
--- a/lib/libc/stdio/fread.3
+++ b/lib/libc/stdio/fread.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: fread.3,v 1.4 2007/05/31 19:19:31 jmc Exp $
+.\"	$OpenBSD: fread.3,v 1.5 2009/07/12 18:45:21 millert Exp $
 .\"
 .\" Copyright (c) 1990, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -31,7 +31,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: May 31 2007 $
+.Dd $Mdocdate: July 12 2009 $
 .Dt FREAD 3
 .Os
 .Sh NAME
@@ -74,6 +74,16 @@ and
 advance the file position indicator for the stream
 by the number of bytes read or written.
 They return the number of objects read or written.
+If
+.Fa size
+or
+.Fa nmemb
+is 0,
+.Fn fread
+and
+.Fn fwrite
+return 0 with no change made to the
+.Fa stream .
 If an error occurs, or the end-of-file is reached,
 the return value is a short object count (or zero).
 .Pp