##### http://autoconf-archive.cryp.to/acx_blas_f77_func.html
#
# SYNOPSIS
#
#   ACX_BLAS_F77_FUNC([ACTION-IF-PASS[, ACTION-IF-FAIL[, ACTION-IF-CROSS-COMPILING]])
#   ACX_BLAS_WITH_F77_FUNC([ACTION-IF-FOUND-AND-PASS[, ACTION-IF-NOT-FOUND-OR-FAIL]])
#
# DESCRIPTION
#
#   These macros are intended as a supplement to the ACX_BLAS macro, to
#   verify that BLAS functions with non-REAL or INTEGER are properly
#   callable from Fortran. This is necessary, for example, if you want
#   to build the LAPACK library on top of the BLAS.
#
#   ACX_BLAS_F77_FUNC uses the defined BLAS_LIBS and Fortran
#   environment to check for compatibility, and takes a specific action
#   in case of success, resp. failure, resp. cross-compilation.
#
#   ACX_BLAS_WITH_F77_FUNC is a drop-in replacement wrapper for
#   ACX_BLAS that calls ACX_BLAS_F77_FUNC after detecting a BLAS
#   library and rejects it on failure (i.e. pretends that no library
#   was found).
#
# LAST MODIFICATION
#
#   2008-03-31
#
# COPYLEFT
#
#   Copyright (c) 2008 Jaroslav Hajek <highegg@gmail.com>
#
#   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 3 of the
#   License, 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.
#
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#   along with this program. If not, see
#   <http://www.gnu.org/licenses/>.
#
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#   modified version as well.

AC_DEFUN([ACX_BLAS_F77_FUNC], [
AC_PREREQ(2.50)
AC_REQUIRE([ACX_BLAS])

# F77 call-compatibility checks
if test "$cross_compiling" = yes ; then
	ifelse($3, ,$1,$3)
elif test x"$acx_blas_ok" = xyes; then
	LIBS="$BLAS_LIBS $LIBS"
	AC_LANG_PUSH(Fortran 77)
# LSAME check (LOGICAL return values)
	AC_MSG_CHECKING([whether LSAME is called correctly from Fortran])
	AC_RUN_IFELSE(AC_LANG_PROGRAM(,[[
      logical lsame,w
      external lsame
      character c1,c2
      c1 = 'A'
      c2 = 'B'
      w = lsame(c1,c2)
      if (w) stop 1
      w = lsame(c1,c1)
      if (.not. w) stop 1
      ]]),[acx_blas_lsame_fcall_ok=yes],
	[acx_blas_lsame_fcall_ok=no])
	AC_MSG_RESULT([$acx_blas_lsame_fcall_ok])
# DDOT check (DOUBLE return values)
	AC_MSG_CHECKING([whether DDOT is called correctly from Fortran])
	AC_RUN_IFELSE(AC_LANG_PROGRAM(,[[
      double precision ddot,a(1),b(1),w
      external ddot
      a(1) = 1e0
      b(1) = 2e0
      w = ddot(1,a,1,b,1)
      if (w .ne. a(1)*b(1)) stop 1
      ]]),[acx_blas_ddot_fcall_ok=yes],
	[acx_blas_ddot_fcall_ok=no])
	AC_MSG_RESULT([$acx_blas_ddot_fcall_ok])
# CDOTU check (COMPLEX return values)
	AC_MSG_CHECKING([whether CDOTU is called correctly from Fortran])
	AC_RUN_IFELSE(AC_LANG_PROGRAM(,[[
      complex cdotu,a(1),b(1),w
      external cdotu
      a(1) = cmplx(1e0,1e0)
      b(1) = cmplx(1e0,2e0)
      w = cdotu(1,a,1,b,1)
      if (w .ne. a(1)*b(1)) stop 1
      ]]),[acx_blas_cdotu_fcall_ok=yes],
	[acx_blas_cdotu_fcall_ok=no])
	AC_MSG_RESULT([$acx_blas_cdotu_fcall_ok])
# ZDOTU check (DOUBLE COMPLEX return values)
	AC_MSG_CHECKING([whether ZDOTU is called correctly from Fortran])
	AC_RUN_IFELSE(AC_LANG_PROGRAM(,[[
      double complex zdotu,a(1),b(1),w
      external zdotu
      a(1) = dcmplx(1d0,1d0)
      b(1) = dcmplx(1d0,2d0)
      w = zdotu(1,a,1,b,1)
      if (w .ne. a(1)*b(1)) stop 1
      ]]),[acx_blas_zdotu_fcall_ok=yes],
	[acx_blas_zdotu_fcall_ok=no])
	AC_MSG_RESULT([$acx_blas_zdotu_fcall_ok])

	AC_LANG_POP(Fortran 77)

# if any of the tests failed, reject the BLAS library
	if test $acx_blas_lsame_fcall_ok = yes \
		-a $acx_blas_ddot_fcall_ok = yes \
		-a $acx_blas_cdotu_fcall_ok = yes \
		-a $acx_blas_zdotu_fcall_ok = yes ; then
		acx_blas_f77_func_ok=yes;
		$1
	else
		acx_blas_f77_func_ok=no;
		$2
	fi
fi

])dnl ACX_BLAS_F77_FUNC

AC_DEFUN([ACX_BLAS_WITH_F77_FUNC], [
AC_PREREQ(2.50)
ACX_BLAS([# disable special action], [])
if test x$acx_blas_ok = xyes ; then
	ACX_BLAS_F77_FUNC(
	[ifelse([$1],,AC_DEFINE(HAVE_BLAS,1,[Define if you have a BLAS library.]),[$1])],
	[acx_blas_ok=no; BLAS_LIBS=])
fi
if test x$acx_blas_ok = xno ; then
	$2
fi
])dnl ACX_BLAS_WITH_F77_FUNC