70 lines
2.6 KiB
Plaintext
70 lines
2.6 KiB
Plaintext
# visibility.m4 serial 1 (gettext-0.15)
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dnl Copyright (C) 2005 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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dnl From Bruno Haible.
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dnl Tests whether the compiler supports the command-line option
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dnl -fvisibility=hidden and the function and variable attributes
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dnl __attribute__((__visibility__("hidden"))) and
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dnl __attribute__((__visibility__("default"))).
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dnl Does *not* test for __visibility__("protected") - which has tricky
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dnl semantics (see the 'vismain' test in glibc) and does not exist e.g. on
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dnl MacOS X.
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dnl Does *not* test for __visibility__("internal") - which has processor
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dnl dependent semantics.
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dnl Does *not* test for #pragma GCC visibility push(hidden) - which is
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dnl "really only recommended for legacy code".
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dnl Set the variable CFLAGS_VISIBILITY.
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dnl Defines and sets the variable HAVE_VISIBILITY.
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dnl Modified for E stuff by Kim Woelders
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AC_DEFUN([EC_C_VISIBILITY],
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[
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AC_REQUIRE([AC_PROG_CC])
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m4_define([ec_c_vis_default], ifelse([$1], [no], [no], [yes]))
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CFLAGS_VISIBILITY=
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HAVE_VISIBILITY=0
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AC_ARG_ENABLE([visibility-hiding],
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[AS_HELP_STRING([--enable-visibility-hiding],
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[enable visibility hiding @<:@default=]ec_c_vis_default[@:>@])],,
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[enable_visibility_hiding=]ec_c_vis_default)
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if test -n "$GCC" -a "x$enable_visibility_hiding" = "xyes"; then
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AC_MSG_CHECKING([for simple visibility declarations])
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AC_CACHE_VAL(ec_cv_cc_visibility, [
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ec_save_CFLAGS="$CFLAGS"
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CFLAGS="$CFLAGS -fvisibility=hidden"
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AC_COMPILE_IFELSE([
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AC_LANG_PROGRAM([[
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]], [[
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extern __attribute__((__visibility__("hidden"))) int hiddenvar;
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extern __attribute__((__visibility__("default"))) int exportedvar;
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extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
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extern __attribute__((__visibility__("default"))) int exportedfunc (void);
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]])
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],
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ec_cv_cc_visibility=yes,
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ec_cv_cc_visibility=no)
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CFLAGS="$ec_save_CFLAGS"])
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AC_MSG_RESULT([$ec_cv_cc_visibility])
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if test $ec_cv_cc_visibility = yes; then
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CFLAGS_VISIBILITY="-fvisibility=hidden"
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HAVE_VISIBILITY=1
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AC_DEFINE(__EXPORT__, __attribute__((__visibility__("default"))), [Symbol is exported])
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fi
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else
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enable_visibility_hiding=no
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fi
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AC_SUBST([CFLAGS_VISIBILITY])
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AC_SUBST([HAVE_VISIBILITY])
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AC_DEFINE_UNQUOTED([HAVE_VISIBILITY], [$HAVE_VISIBILITY],
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[Define to 1 or 0, depending whether the compiler supports simple visibility declarations.])
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])
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