Re: [libvirt] [PATCH] logging: confirm that we want to ignore a write error

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(a)redhat.com&gt; 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); --