osinfo_loader.c contains a few local hacks to avoid gcc warnings about set-but-not-read variables. While they are good to silence gcc, they also cause warnings from the Coverity checker. Use the ignore_value() macro from gnulib to avoid these warnings as they don't cause Coverity warnings. --- osinfo/ignore-value.h | 47 +++++++++++++++++++++++++++++++++++++++++++++++ osinfo/osinfo_loader.c | 19 ++++++------------- 2 files changed, 53 insertions(+), 13 deletions(-) create mode 100644 osinfo/ignore-value.h diff --git a/osinfo/ignore-value.h b/osinfo/ignore-value.h new file mode 100644 index 0000000..6bab971 --- /dev/null +++ b/osinfo/ignore-value.h @@ -0,0 +1,47 @@ +/* ignore a function return without a compiler warning + + Copyright (C) 2008-2013 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +/* Written by Jim Meyering, Eric Blake and Pádraig Brady. */ + +/* Use "ignore_value" to avoid a warning when using a function declared with + gcc's warn_unused_result attribute, but for which you really do want to + ignore the result. Traditionally, people have used a "(void)" cast to + indicate that a function's return value is deliberately unused. However, + if the function is declared with __attribute__((warn_unused_result)), + gcc issues a warning even with the cast. + + Caution: most of the time, you really should heed gcc's warning, and + check the return value. However, in those exceptional cases in which + you're sure you know what you're doing, use this function. + + For the record, here's one of the ignorable warnings: + "copy.c:233: warning: ignoring return value of 'fchown', + declared with attribute warn_unused_result". */ + +#ifndef _GL_IGNORE_VALUE_H +# define _GL_IGNORE_VALUE_H + +/* The __attribute__((__warn_unused_result__)) feature + is available in gcc versions 3.4 and newer, + while the typeof feature has been available since 2.7 at least. */ +# if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 4) +# define ignore_value(x) ((void) (x)) +# else +# define ignore_value(x) (({ __typeof__ (x) __x = (x); (void) __x; })) +# endif + +#endif diff --git a/osinfo/osinfo_loader.c b/osinfo/osinfo_loader.c index d713767..76e9bc2 100644 --- a/osinfo/osinfo_loader.c +++ b/osinfo/osinfo_loader.c @@ -34,6 +34,7 @@ #include <libxml/tree.h> #include <libxml/xpath.h> #include <libxml/xmlreader.h> +#include "ignore-value.h" #include "osinfo_install_script_private.h" #include "osinfo_device_driver_private.h" @@ -1486,20 +1487,15 @@ osinfo_loader_process_file_reg_ids(OsinfoLoader *loader, WANT_ID(subvendor_id); WANT_ID(subdevice_id); WANT_REST(subsystem); - - /* Pretend we 'use' these variables to get around - * 'gcc' warnings about set-but-not-read vars */ - if (subvendor_id || subdevice_id || subsystem) - subsystem = subsystem; + ignore_value(subvendor_id); + ignore_value(subdevice_id); + ignore_value(subsystem); } else { FREE_BUF(device_buf); WANT_ID(device_id); WANT_REST(device); SAVE_BUF(device_buf); - - /* Trick gcc set-by-not-read-vars warning */ - if (device) - device = device; + ignore_value(device); gchar *id = g_strdup_printf("%s/%s/%s", baseURI, vendor_id, device_id); @@ -1521,10 +1517,7 @@ osinfo_loader_process_file_reg_ids(OsinfoLoader *loader, WANT_ID(vendor_id); WANT_REST(vendor); SAVE_BUF(vendor_buf); - - /* Trick gcc set-by-not-read-vars warning */ - if (vendor) - vendor = vendor; + ignore_value(vendor); } done: -- 1.8.1 _______________________________________________ Libosinfo mailing list Libosinfo@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libosinfo
