~drizzle-trunk/drizzle/development

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);],

        [],

        [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"

      NO_VISIBILITY="-fvisibility=default"

      HAVE_VISIBILITY=1

    fi

  ])

  AS_IF([test "x$SUNCC" = "xyes"],[

    CFLAG_VISIBILITY="-xldscope=hidden"

    NO_VISIBILITY="-xldscope=global"

    HAVE_VISIBILITY=1

  ])

  AC_SUBST([CFLAG_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} ${CFLAG_VISIBILITY}"

])