Rename module 'link-warning' to 'snippet/link-warning'.

[gnulib.git] / build-aux / snippet / link-warning.h

diff --git a/build-aux/snippet/link-warning.h b/build-aux/snippet/link-warning.h
new file mode 100644 (file)
index 0000000..84708ff
--- /dev/null
+++ b/build-aux/snippet/link-warning.h
@@ -0,0 +1,49 @@
+/* A C macro for emitting link time warnings.
+   Copyright (C) 1995, 1997, 2000, 2002-2003, 2007, 2009-2011 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 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/>.  */
+
+#if @HAVE_FEATURES_H@
+# include <features.h> /* for __GLIBC__, __UCLIBC__ */
+#endif
+
+/* GL_LINK_WARNING("literal string") arranges to emit the literal string as
+   a linker warning on most glibc systems.
+   We use a linker warning rather than a preprocessor warning, because
+   #warning cannot be used inside macros.  */
+#ifndef GL_LINK_WARNING
+  /* This works on platforms with GNU ld and ELF object format.
+     Testing __GLIBC__ is sufficient for asserting that GNU ld is in use.
+     Testing __ELF__ guarantees the ELF object format.
+     Testing __GNUC__ is necessary for the compound expression syntax.  */
+# if (defined __GLIBC__ || defined __UCLIBC__) && defined __ELF__ && defined __GNUC__
+#  define GL_LINK_WARNING(message) \
+     GL_LINK_WARNING1 (__FILE__, __LINE__, message)
+#  define GL_LINK_WARNING1(file, line, message) \
+     GL_LINK_WARNING2 (file, line, message)  /* macroexpand file and line */
+#  define GL_LINK_WARNING2(file, line, message) \
+     GL_LINK_WARNING3 (file ":" #line ": warning: " message)
+#  define GL_LINK_WARNING3(message) \
+     ({ static const char warning[sizeof (message)]             \
+          __attribute__ ((__unused__,                           \
+                          __section__ (".gnu.warning"),         \
+                          __aligned__ (1)))                     \
+          = message "\n";                                       \
+        (void)0;                                                \
+     })
+# else
+#  define GL_LINK_WARNING(message) ((void) 0)
+# endif
+#endif