You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
77 lines
3.3 KiB
77 lines
3.3 KiB
# visibility.m4 serial 5 (gettext-0.18.2) |
|
dnl Copyright (C) 2005, 2008, 2010-2017 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 Mac OS 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 |
|
dnl First, check whether -Werror can be added to the command line, or |
|
dnl whether it leads to an error because of some other option that the |
|
dnl user has put into $CC $CFLAGS $CPPFLAGS. |
|
AC_MSG_CHECKING([whether the -Werror option is usable]) |
|
AC_CACHE_VAL([gl_cv_cc_vis_werror], [ |
|
gl_save_CFLAGS="$CFLAGS" |
|
CFLAGS="$CFLAGS -Werror" |
|
AC_COMPILE_IFELSE( |
|
[AC_LANG_PROGRAM([[]], [[]])], |
|
[gl_cv_cc_vis_werror=yes], |
|
[gl_cv_cc_vis_werror=no]) |
|
CFLAGS="$gl_save_CFLAGS"]) |
|
AC_MSG_RESULT([$gl_cv_cc_vis_werror]) |
|
dnl Now check whether visibility declarations are supported. |
|
AC_MSG_CHECKING([for simple visibility declarations]) |
|
AC_CACHE_VAL([gl_cv_cc_visibility], [ |
|
gl_save_CFLAGS="$CFLAGS" |
|
CFLAGS="$CFLAGS -fvisibility=hidden" |
|
dnl We use the option -Werror and a function dummyfunc, because on some |
|
dnl platforms (Cygwin 1.7) the use of -fvisibility triggers a warning |
|
dnl "visibility attribute not supported in this configuration; ignored" |
|
dnl at the first function definition in every compilation unit, and we |
|
dnl don't want to use the option in this case. |
|
if test $gl_cv_cc_vis_werror = yes; then |
|
CFLAGS="$CFLAGS -Werror" |
|
fi |
|
AC_COMPILE_IFELSE( |
|
[AC_LANG_PROGRAM( |
|
[[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); |
|
void dummyfunc (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.]) |
|
])
|
|
|