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+##### 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.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program. If not, see
+#   <http://www.gnu.org/licenses/>.
+#
+#   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.
+#
+#   This special exception to the GPL applies to versions of the
+#   Autoconf Macro released by the Autoconf Macro Archive. When you
+#   make and distribute a modified version of the Autoconf Macro, you
+#   may extend this special exception to the GPL to apply to your
+#   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