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| author | Cristian RodrÃguez <cristian.rodriguez@opensuse.org> | 2010-11-15 20:31:25 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2010-11-15 20:31:25 +0100 |
| commit | 37dac00e2ad6445f496e68fcf815723432ecb5a8 (patch) | |
| tree | 9c97e3f99a1663970c578ad879903ced82277415 /m4 | |
| parent | 485d30a8a89e7500b0df4291fa4dfc33b894998c (diff) | |
| download | libmnl-37dac00e2ad6445f496e68fcf815723432ecb5a8.tar.gz libmnl-37dac00e2ad6445f496e68fcf815723432ecb5a8.zip | |
src: implement both GCC visibility support and export script
Read "How to write shared libraries" from Ulrich Drepper for more
information on this patch. Specifically section 2.2: Export control
and section 3: Maintaining APIs and ABIs.
Signed-off-by: Cristian RodrÃguez <cristian.rodriguez@opensuse.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'm4')
| -rw-r--r-- | m4/visibility.m4 | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/m4/visibility.m4 b/m4/visibility.m4 new file mode 100644 index 0000000..2ff6330 --- /dev/null +++ b/m4/visibility.m4 @@ -0,0 +1,52 @@ +# visibility.m4 serial 1 (gettext-0.15) +dnl Copyright (C) 2005 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +dnl From Bruno Haible. + +dnl Tests whether the compiler supports the command-line option +dnl -fvisibility=hidden and the function and variable attributes +dnl __attribute__((__visibility__("hidden"))) and +dnl __attribute__((__visibility__("default"))). +dnl Does *not* test for __visibility__("protected") - which has tricky +dnl semantics (see the 'vismain' test in glibc) and does not exist e.g. on +dnl MacOS X. +dnl Does *not* test for __visibility__("internal") - which has processor +dnl dependent semantics. +dnl Does *not* test for #pragma GCC visibility push(hidden) - which is +dnl "really only recommended for legacy code". +dnl Set the variable CFLAG_VISIBILITY. +dnl Defines and sets the variable HAVE_VISIBILITY. + +AC_DEFUN([gl_VISIBILITY], +[ + AC_REQUIRE([AC_PROG_CC]) + CFLAG_VISIBILITY= + HAVE_VISIBILITY=0 + if test -n "$GCC"; then + AC_MSG_CHECKING([for simple visibility declarations]) + AC_CACHE_VAL(gl_cv_cc_visibility, [ + gl_save_CFLAGS="$CFLAGS" + CFLAGS="$CFLAGS -fvisibility=hidden" + AC_TRY_COMPILE( + [extern __attribute__((__visibility__("hidden"))) int hiddenvar; + extern __attribute__((__visibility__("default"))) int exportedvar; + extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void); + extern __attribute__((__visibility__("default"))) int exportedfunc (void);], + [], + gl_cv_cc_visibility=yes, + gl_cv_cc_visibility=no) + CFLAGS="$gl_save_CFLAGS"]) + AC_MSG_RESULT([$gl_cv_cc_visibility]) + if test $gl_cv_cc_visibility = yes; then + CFLAG_VISIBILITY="-fvisibility=hidden" + HAVE_VISIBILITY=1 + fi + fi + AC_SUBST([CFLAG_VISIBILITY]) + AC_SUBST([HAVE_VISIBILITY]) + AC_DEFINE_UNQUOTED([HAVE_VISIBILITY], [$HAVE_VISIBILITY], + [Define to 1 or 0, depending whether the compiler supports simple visibility declarations.]) +]) |