dnl Copyright (C) 1993-2006 Free Software Foundation, Inc. dnl This file is free software, distributed under the terms of the GNU dnl General Public License. As a special exception to the GNU General dnl Public License, this file may be distributed as part of a program dnl that contains a configuration script generated by Autoconf, under dnl the same distribution terms as the rest of that program. dnl From Bruno Haible, Marcus Daniels, Paul Eggert. AC_PREREQ(2.13) AC_DEFUN([CL_LONGDOUBLE], [AC_CACHE_CHECK(for long double type, cl_cv_c_longdouble, [ AC_TRY_RUN([ #include int main() { long double x = 2.7182818284590452354L; x = x*x; exit (x==0.0L); } ], cl_cv_c_longdouble=yes, cl_cv_c_longdouble=no, [ dnl When cross-compiling, use the test from gnulib. AC_TRY_COMPILE([ /* The Stardent Vistra knows sizeof(long double), but does not support it. */ long double foo = 0.0; /* On Ultrix 4.3 cc, long double is 4 and double is 8. */ int array [2*(sizeof(long double) >= sizeof(double)) - 1]; ], , cl_cv_c_longdouble=yes, cl_cv_c_longdouble=no)]) ]) if test $cl_cv_c_longdouble = yes; then AC_DEFINE(HAVE_LONGDOUBLE) fi ])