1 /* A C macro for emitting link time warnings.
2 Copyright (C) 1995, 1997, 2000, 2002-2003, 2007, 2009-2011 Free Software
5 This program is free software: you can redistribute it and/or modify it
6 under the terms of the GNU Lesser General Public License as published
7 by the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19 # include <features.h> /* for __GLIBC__, __UCLIBC__ */
22 /* GL_LINK_WARNING("literal string") arranges to emit the literal string as
23 a linker warning on most glibc systems.
24 We use a linker warning rather than a preprocessor warning, because
25 #warning cannot be used inside macros. */
26 #ifndef GL_LINK_WARNING
27 /* This works on platforms with GNU ld and ELF object format.
28 Testing __GLIBC__ is sufficient for asserting that GNU ld is in use.
29 Testing __ELF__ guarantees the ELF object format.
30 Testing __GNUC__ is necessary for the compound expression syntax. */
31 # if (defined __GLIBC__ || defined __UCLIBC__) && defined __ELF__ && defined __GNUC__
32 # define GL_LINK_WARNING(message) \
33 GL_LINK_WARNING1 (__FILE__, __LINE__, message)
34 # define GL_LINK_WARNING1(file, line, message) \
35 GL_LINK_WARNING2 (file, line, message) /* macroexpand file and line */
36 # define GL_LINK_WARNING2(file, line, message) \
37 GL_LINK_WARNING3 (file ":" #line ": warning: " message)
38 # define GL_LINK_WARNING3(message) \
39 ({ static const char warning[sizeof (message)] \
40 __attribute__ ((__unused__, \
41 __section__ (".gnu.warning"), \
47 # define GL_LINK_WARNING(message) ((void) 0)