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Member "pcre-8.43/m4/pcre_visibility.m4" (31 Jan 2014, 4338 Bytes) of package /linux/misc/pcre-8.43.tar.bz2:


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    1 # visibility.m4 serial 4 (gettext-0.18.2)
    2 dnl Copyright (C) 2005, 2008, 2010-2011 Free Software Foundation, Inc.
    3 dnl This file is free software; the Free Software Foundation
    4 dnl gives unlimited permission to copy and/or distribute it,
    5 dnl with or without modifications, as long as this notice is preserved.
    6 
    7 dnl From Bruno Haible.
    8 
    9 dnl Tests whether the compiler supports the command-line option
   10 dnl -fvisibility=hidden and the function and variable attributes
   11 dnl __attribute__((__visibility__("hidden"))) and
   12 dnl __attribute__((__visibility__("default"))).
   13 dnl Does *not* test for __visibility__("protected") - which has tricky
   14 dnl semantics (see the 'vismain' test in glibc) and does not exist e.g. on
   15 dnl MacOS X.
   16 dnl Does *not* test for __visibility__("internal") - which has processor
   17 dnl dependent semantics.
   18 dnl Does *not* test for #pragma GCC visibility push(hidden) - which is
   19 dnl "really only recommended for legacy code".
   20 dnl Set the variable CFLAG_VISIBILITY.
   21 dnl Defines and sets the variable HAVE_VISIBILITY.
   22 
   23 dnl Modified to fit with PCRE build environment by Cristian Rodríguez.
   24 
   25 AC_DEFUN([PCRE_VISIBILITY],
   26 [
   27   AC_REQUIRE([AC_PROG_CC])
   28   VISIBILITY_CFLAGS=
   29   VISIBILITY_CXXFLAGS=
   30   HAVE_VISIBILITY=0
   31   if test -n "$GCC"; then
   32     dnl First, check whether -Werror can be added to the command line, or
   33     dnl whether it leads to an error because of some other option that the
   34     dnl user has put into $CC $CFLAGS $CPPFLAGS.
   35     AC_MSG_CHECKING([whether the -Werror option is usable])
   36     AC_CACHE_VAL([pcre_cv_cc_vis_werror], [
   37       pcre_save_CFLAGS="$CFLAGS"
   38       CFLAGS="$CFLAGS -Werror"
   39       AC_COMPILE_IFELSE(
   40         [AC_LANG_PROGRAM([[]], [[]])],
   41         [pcre_cv_cc_vis_werror=yes],
   42         [pcre_cv_cc_vis_werror=no])
   43       CFLAGS="$pcre_save_CFLAGS"])
   44     AC_MSG_RESULT([$pcre_cv_cc_vis_werror])
   45     dnl Now check whether visibility declarations are supported.
   46     AC_MSG_CHECKING([for simple visibility declarations])
   47     AC_CACHE_VAL([pcre_cv_cc_visibility], [
   48       pcre_save_CFLAGS="$CFLAGS"
   49       CFLAGS="$CFLAGS -fvisibility=hidden"
   50       dnl We use the option -Werror and a function dummyfunc, because on some
   51       dnl platforms (Cygwin 1.7) the use of -fvisibility triggers a warning
   52       dnl "visibility attribute not supported in this configuration; ignored"
   53       dnl at the first function definition in every compilation unit, and we
   54       dnl don't want to use the option in this case.
   55       if test $pcre_cv_cc_vis_werror = yes; then
   56         CFLAGS="$CFLAGS -Werror"
   57       fi
   58       AC_COMPILE_IFELSE(
   59         [AC_LANG_PROGRAM(
   60            [[extern __attribute__((__visibility__("hidden"))) int hiddenvar;
   61              extern __attribute__((__visibility__("default"))) int exportedvar;
   62              extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
   63              extern __attribute__((__visibility__("default"))) int exportedfunc (void);
   64              void dummyfunc (void) {}
   65            ]],
   66            [[]])],
   67         [pcre_cv_cc_visibility=yes],
   68         [pcre_cv_cc_visibility=no])
   69       CFLAGS="$pcre_save_CFLAGS"])
   70     AC_MSG_RESULT([$pcre_cv_cc_visibility])
   71     if test $pcre_cv_cc_visibility = yes; then
   72       VISIBILITY_CFLAGS="-fvisibility=hidden"
   73       VISIBILITY_CXXFLAGS="-fvisibility=hidden -fvisibility-inlines-hidden"
   74       HAVE_VISIBILITY=1
   75       AC_DEFINE(PCRE_EXP_DECL, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
   76       AC_DEFINE(PCRE_EXP_DEFN, [__attribute__ ((visibility ("default")))], [to make a symbol visible])
   77       AC_DEFINE(PCRE_EXP_DATA_DEFN, [__attribute__ ((visibility ("default")))], [to make a symbol visible])
   78       AC_DEFINE(PCREPOSIX_EXP_DECL, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
   79       AC_DEFINE(PCREPOSIX_EXP_DEFN, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
   80       AC_DEFINE(PCRECPP_EXP_DECL, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
   81       AC_DEFINE(PCRECPP_EXP_DEFN, [__attribute__ ((visibility ("default")))], [to make a symbol visible])
   82     fi
   83   fi
   84   AC_SUBST([VISIBILITY_CFLAGS])
   85   AC_SUBST([VISIBILITY_CXXFLAGS])
   86   AC_SUBST([HAVE_VISIBILITY])
   87   AC_DEFINE_UNQUOTED([HAVE_VISIBILITY], [$HAVE_VISIBILITY],
   88     [Define to 1 if the compiler supports simple visibility declarations.])
   89 ])