#!/bin/sh
# have-func --- check for existence of library function

# Copyright (C) 1996 Noah S. Friedman
# Author: Noah Friedman <friedman@prep.ai.mit.edu>
# Created: 1996-09-30

# $Id: have-func,v 2.1 1996/09/30 19:08:23 friedman Exp $

# This program 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, or (at your option)
# any later version.
#
# This program 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 this program; if not, you can either send email to this
# program's maintainer or write to: The Free Software Foundation,
# Inc.; 59 Temple Place, Suite 330; Boston, MA 02111-1307, USA.

# Commentary:

# Zero exit status if the named function exists, 1 otherwise.
# Note: this script may lie if there are unrelated compilation problems.

# Code:

case "$#" in
  1 ) : ;;
  2 )
    progname=`echo "$0" | sed -e 's/[^\/]*\///g'`
    echo "Usage: $progname [function name]" 1>&2
    exit 1
   ;;
esac

func="$1"
file="functest$$"

trap 'exitstat=$?; rm -f $file.c $file.o $file; exit $exitstat' 0 1 2 3 15

cat > "$file.c" <<__EOF__
/* System header to define __stub macros and hopefully few prototypes,
    which can conflict with char $ac_func(); below.  */
#include <assert.h>

/* Override any gcc2 internal prototype to avoid an error.  */
/* We use char because int might match the return type of a gcc2
    builtin and then its argument prototype would still apply.  */
char $func ();

int main () { t (); return 0; }
int t ()
{
  /* The GNU C library defines this for functions which it implements
   * to always fail with ENOSYS.  Some functions are actually named
   * something starting with __ and the normal name is an alias.
   */
#if defined (__stub_$func) || defined (__stub___$func)
  choke me
#else
    $func ();
#endif
  return 0;
}
__EOF__

if ${CC-cc} ${CFLAGS} $file.c -o $file ${LOADLIBES} 2> /dev/null &&
   test -f "$file"
then
  exit 0
fi

exit 1

# have-func ends here