Ignoring a write failure is a big deal, so when you do that deliberately,
it's worth marking in such a way that code analyzers don't report a
false positive. Until a year or so ago, people thought using (void)
would be enough. But newer gcc warns in spite of that (for functions
marked with the warn_unused_result attribute), so now we use the
ignore_value function from gnulib.
A coverity warning prompted the change below, but if we declare
saferead with the warn_unused_result attribute, gcc would, too.
>From 62d2c7f69608407afa9a4bf38f0d29ea3eec88f5 Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@xxxxxxxxxx>
Date: Mon, 18 Jan 2010 11:51:01 +0100
Subject: [PATCH] logging: confirm that we want to ignore a write error
* src/util/logging.c (virLogMessage): Include "ignore-value.h".
Use it to ignore the return value of safewrite.
Use STDERR_FILENO, rather than "2".
* bootstrap (modules): Add ignore-value.
* gnulib: Update to latest, for ignore-value that is now LGPLv2+.
---
.gnulib | 2 +-
bootstrap | 1 +
src/util/logging.c | 5 +++--
3 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/.gnulib b/.gnulib
index 4c52807..146d914 160000
--- a/.gnulib
+++ b/.gnulib
@@ -1 +1 @@
-Subproject commit 4c52807f41f238cf0e352317b2dc54f9ba0f0c4f
+Subproject commit 146d9145073e62a2096a2d6b33f75e93908fedf3
diff --git a/bootstrap b/bootstrap
index c07d851..aec5d05 100755
--- a/bootstrap
+++ b/bootstrap
@@ -76,6 +76,7 @@ getpass
gettext
gitlog-to-changelog
gnumakefile
+ignore-value
inet_pton
ioctl
maintainer-makefile
diff --git a/src/util/logging.c b/src/util/logging.c
index 6bd8469..3b3c309 100644
--- a/src/util/logging.c
+++ b/src/util/logging.c
@@ -1,7 +1,7 @@
/*
* logging.c: internal logging and debugging
*
- * Copyright (C) 2008 Red Hat, Inc.
+ * Copyright (C) 2008, 2010 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@@ -34,6 +34,7 @@
#include <syslog.h>
#endif
+#include "ignore-value.h"
#include "logging.h"
#include "memory.h"
#include "util.h"
@@ -579,7 +580,7 @@ void virLogMessage(const char *category, int priority, const char *funcname,
msg, len, virLogOutputs[i].data);
}
if ((virLogNbOutputs == 0) && (flags != 1))
- safewrite(2, msg, len);
+ ignore_value (safewrite(STDERR_FILENO, msg, len));
virLogUnlock();
VIR_FREE(msg);
--
1.6.6.638.g2bc54
--
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