## Copyright (c) 2004-2007 Daniel Elstner <daniel.kitta@gmail.com></daniel.kitta@gmail.com>

##

## This file is part of danielk's Autostuff.

##

## danielk's Autostuff is free software; you can redistribute it and/or

## modify it under the terms of the GNU General Public License as published

## by the Free Software Foundation; either version 2 of the License, or (at

## your option) any later version.

##

## danielk's Autostuff is distributed in the hope that it will be useful, but

## WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License

## for more details.

##

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

## with danielk's Autostuff; if not, write to the Free Software Foundation,

## Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

#serial 20070116

## DK_ARG_ENABLE_WARNINGS(variable, min-flags, max-flags, [deprecation-prefixes])

##

## Provide the --enable-warnings configure argument, set to "min" by default.

## <min-flags> and <max-flags> should be space-separated lists of compiler</max-flags></min-flags>

## warning flags to use with --enable-warnings=min or --enable-warnings=max,

## respectively. Warning level "fatal" is the same as "max" but in addition

## enables -Werror mode.

##

## If not empty, <deprecation-prefixes> should be a list of module prefixes</deprecation-prefixes>

## which is expanded to -D<module>_DISABLE_DEPRECATED flags if fatal warnings</module>

## are enabled, too.

##

AC_DEFUN([DK_ARG_ENABLE_WARNINGS],

[dnl

m4_if([$3],, [AC_FATAL([3 arguments expected])])[]dnl

dnl

AC_ARG_ENABLE([warnings], [AS_HELP_STRING(

  [--enable-warnings=@<:@min|max|fatal|no@:>@],

  [control compiler pickyness @<:@min@:>@])],

  [dk_enable_warnings=$enableval],

  [dk_enable_warnings=min])[]dnl

dk_lang=

case $ac_compile in

  *'$CXXFLAGS '*)

    dk_lang='C++'

    dk_cc=$CXX

    dk_conftest=conftest.${ac_ext-cc}

    ;;

  *'$CFLAGS '*)

    dk_lang=C

    dk_cc=$CC

    dk_conftest=conftest.${ac_ext-c}

    ;;

esac

AS_IF([test "x$dk_lang" != x],

[

  AC_MSG_CHECKING([which $dk_lang compiler warning flags to use])

  case $dk_enable_warnings in

    no) dk_warning_flags=;;

    max) dk_warning_flags="$3";;

    fatal) dk_warning_flags="$3 -Werror";;

    *) dk_warning_flags="$2";;

  esac

  dk_deprecation_flags=

m4_if([$4],,, [

  AS_IF([test "x$dk_enable_warnings" = xfatal],

  [

    dk_deprecation_prefixes="$4"

    for dk_prefix in $dk_deprecation_prefixes

    do

      dk_deprecation_flags="${dk_deprecation_flags}-D${dk_prefix}_DISABLE_DEPRECATED "

    done

  ])

])[]dnl

  dk_tested_flags=

  AS_IF([test "x$dk_warning_flags" != x],

  [

    # Keep in mind that the dummy source must be devoid of any

    # problems that might cause diagnostics.

    AC_LANG_CONFTEST([AC_LANG_SOURCE(

      [[int main(int argc, char** argv) { return (argv != 0) ? argc : 0; }]])])

    for dk_flag in $dk_warning_flags

    do

      # Test whether the compiler accepts the flag. GCC doesn't bail

      # out when given an unsupported flag but prints a warning, so

      # check the compiler output instead.

      dk_cc_out=`$dk_cc $dk_tested_flags $dk_flag -c "$dk_conftest" 2>&1 || echo failed`

      rm -f "conftest.${OBJEXT-o}"

      AS_IF([test "x$dk_cc_out" = x],

      [

        AS_IF([test "x$dk_tested_flags" = x],

              [dk_tested_flags=$dk_flag],

              [dk_tested_flags="$dk_tested_flags $dk_flag"])

      ], [

        echo "$dk_cc_out" >&AS_MESSAGE_LOG_FD

      ])

    done

    rm -f "$dk_conftest"

  ])

  dk_all_flags=$dk_deprecation_flags$dk_tested_flags

  AC_SUBST([$1], [$dk_all_flags])

  test "x$dk_all_flags" != x || dk_all_flags=none

  AC_MSG_RESULT([$dk_all_flags])

])

])