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dnl Copyright (C) 2005, 2008 Free Software Foundation, Inc.
dnl Copyright (C) 2009 Monty Taylor
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([PANDORA_CHECK_VISIBILITY],
[
AC_REQUIRE([AC_PROG_CC])
CFLAG_VISIBILITY=
HAVE_VISIBILITY=0
AS_IF([test -n "$GCC"],[
AC_MSG_CHECKING([for simple visibility declarations])
AC_CACHE_VAL([gl_cv_cc_visibility], [
gl_save_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS -fvisibility=hidden -Werror"
AC_TRY_COMPILE(
[extern __attribute__((__visibility__("hidden"))) int hiddenvar;
extern __attribute__((__visibility__("default"))) int exportedvar;
extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
extern __attribute__((__visibility__("default"))) int exportedfunc (void);],
[],[
case "$host_os" in
*darwin*)
gl_cv_cc_visibility=no
;;
*)
gl_cv_cc_visibility=yes
;;
esac
],[gl_cv_cc_visibility=no])
CFLAGS="$gl_save_CFLAGS"])
AC_MSG_RESULT([$gl_cv_cc_visibility])
if test $gl_cv_cc_visibility = yes; then
CFLAG_VISIBILITY="-fvisibility=hidden"
CXXFLAG_VISIBILITY="-fvisibility=hidden -fvisibility-inlines-hidden"
NO_VISIBILITY="-fvisibility=default"
HAVE_VISIBILITY=1
fi
])
AS_IF([test "x$SUNCC" = "xyes"],[
CFLAG_VISIBILITY="-xldscope=hidden"
CXXFLAG_VISIBILITY="-xldscope=hidden"
NO_VISIBILITY="-xldscope=global"
HAVE_VISIBILITY=1
])
AC_SUBST([CFLAG_VISIBILITY])
AC_SUBST([CXXFLAG_VISIBILITY])
AC_SUBST([NO_VISIBILITY])
AC_SUBST([HAVE_VISIBILITY])
AC_DEFINE_UNQUOTED([HAVE_VISIBILITY], [$HAVE_VISIBILITY],
[Define to 1 or 0, depending whether the compiler supports simple visibility declarations.])
])
AC_DEFUN([PANDORA_ENABLE_VISIBILITY],[
AC_REQUIRE([PANDORA_CHECK_VISIBILITY])
AM_CFLAGS="${AM_CFLAGS} ${CFLAG_VISIBILITY}"
AM_CXXFLAGS="${AM_CXXFLAGS} ${CXXFLAG_VISIBILITY}"
])
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