dnl Copyright (c) 2008 Diego Pettenò <flameeyes@gmail.com>

dnl

dnl This program is free software; you can redistribute it and/or modify

dnl it under the terms of the GNU General Public License as published by

dnl the Free Software Foundation; either version 2, or (at your option)

dnl any later version.

dnl

dnl This program is distributed in the hope that it will be useful,

dnl but WITHOUT ANY WARRANTY; without even the implied warranty of

dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

dnl GNU General Public License for more details.

dnl

dnl You should have received a copy of the GNU General Public License

dnl along with this program; if not, write to the Free Software

dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

dnl 02110-1301, USA.

dnl

dnl As a special exception, the copyright owners of the

dnl macro gives unlimited permission to copy, distribute and modify the

dnl configure scripts that are the output of Autoconf when processing the

dnl Macro. You need not follow the terms of the GNU General Public

dnl License when using or distributing such scripts, even though portions

dnl of the text of the Macro appear in them. The GNU General Public

dnl License (GPL) does govern all other use of the material that

dnl constitutes the Autoconf Macro.

dnl 

dnl This special exception to the GPL applies to versions of the

dnl Autoconf Macro released by this project. When you make and

dnl distribute a modified version of the Autoconf Macro, you may extend

dnl this special exception to the GPL to apply to your modified version as

dnl well.

dnl ACF_SEARCH_FUNCTION([function name],

dnl                     [m4 list of libraries],

dnl                     [action if found],

dnl                     [action if not found],

dnl                     [test source])

dnl

dnl Improved modified version of AC_SEARCH_LIBS, with some

dnl differences:

dnl  - it accepts an m4 list for libraries to allow compound libraries

dnl    instead of using the other-libraries parameter;

dnl  - action if not found is only invoked when the function is not

dnl    found at all;

dnl  - an optional parameter allows for custom source code for testing

dnl    (allowing to search for functions that are actually aliased).

AC_DEFUN([ACF_SEARCH_FUNCTION], [

  m4_pushdef([search_sourcecode], [

    m4_default([$5], [

      AC_LANG_CALL([], [$1])

    ])

  ])

  m4_pushdef([cache_variable], AS_TR_SH([acf_cv_library_$1]))

  m4_pushdef([action_if_found],

    m4_default([$3], [LIBS="$LIBS $]cache_variable["]))

  m4_pushdef([action_if_not_found], m4_default([$4], [:]))

  AC_CACHE_CHECK([for library containing $1],

    cache_variable,

    [while true; do

       m4_foreach([library], [, $2], [

         save_libs=$LIBS

	 LIBS="$LIBS library"

         AC_LINK_IFELSE(search_sourcecode,

           cache_variable=" library")

         LIBS=$save_libs

	 AS_IF(test -n "$cache_variable", [break])

       ])

       break

     done

    ])

  m4_popdef([search_sourcecode])

  AS_IF(test -n "$cache_variable",

    m4_n([action_if_found]),

    m4_n([action_if_not_found])

    )

  m4_popdef([cache_variable])

])