#
# Copyright © 2006 Steven G. Johnson <stevenj@alum.mit.edu>
#
#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 of the License, or (at
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#
#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, write to the Free Software
#Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
#USA.
#
#As a special exception, the respective Autoconf Macro's copyright
#owner gives unlimited permission to copy, distribute and modify the
#configure scripts that are the output of Autoconf when processing the
#Macro. You need not follow the terms of the GNU General Public License
#when using or distributing such scripts, even though portions of the
#text of the Macro appear in them. The GNU General Public License (GPL)
#does govern all other use of the material that constitutes the
#Autoconf Macro.
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#
# http://autoconf-archive.cryp.to/ax_openmp.html
#

AC_DEFUN([AX_OPENMP], [
AC_PREREQ(2.59) dnl for _AC_LANG_PREFIX

AC_CACHE_CHECK([for OpenMP flag of _AC_LANG compiler], ax_cv_[]_AC_LANG_ABBREV[]_openmp, [save[]_AC_LANG_PREFIX[]FLAGS=$[]_AC_LANG_PREFIX[]FLAGS
ax_cv_[]_AC_LANG_ABBREV[]_openmp=unknown
# Flags to try:  -fopenmp (gcc), -openmp (icc), -mp (SGI & PGI),
#                -xopenmp (Sun), -omp (Tru64), -qsmp=omp (AIX), none
ax_openmp_flags="-openmp -mp=numa -mp=nonuma -mp -xopenmp -omp -qsmp=omp -fopenmp none"
if test "x$OPENMP_[]_AC_LANG_PREFIX[]FLAGS" != x; then
  ax_openmp_flags="$OPENMP_[]_AC_LANG_PREFIX[]FLAGS $ax_openmp_flags"
fi
for ax_openmp_flag in $ax_openmp_flags; do
  case $ax_openmp_flag in
    none) []_AC_LANG_PREFIX[]FLAGS="$save[]_AC_LANG_PREFIX[] $_AC_LANG_PREFIX[]FLAGS" ;;
    *) []_AC_LANG_PREFIX[]FLAGS="$save[]_AC_LANG_PREFIX[]FLAGS $ax_openmp_flag";;
  esac
  AC_TRY_LINK_FUNC(omp_set_num_threads,
        [ax_cv_[]_AC_LANG_ABBREV[]_openmp=$ax_openmp_flag; break])
done
[]_AC_LANG_PREFIX[]FLAGS=$save[]_AC_LANG_PREFIX[]FLAGS
])
if test "x$ax_cv_[]_AC_LANG_ABBREV[]_openmp" = "xunknown"; then
  m4_default([$2],:)
else
  if test "x$ax_cv_[]_AC_LANG_ABBREV[]_openmp" != "xnone"; then
    OPENMP_[]_AC_LANG_PREFIX[]FLAGS=$ax_cv_[]_AC_LANG_ABBREV[]_openmp
  fi
  m4_default([$1], [AC_DEFINE(HAVE_OPENMP,1,[Define if OpenMP is enabled])])
fi
])dnl AX_OPENMP