1 # ldexpl.m4 serial 16 2 dnl Copyright (C) 2007-2012 Free Software Foundation, Inc. 3 dnl This file is free software; the Free Software Foundation 4 dnl gives unlimited permission to copy and/or distribute it, 5 dnl with or without modifications, as long as this notice is preserved. 6 7 AC_DEFUN([gl_FUNC_LDEXPL], 8 [ 9 AC_REQUIRE([gl_MATH_H_DEFAULTS]) 10 AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE]) 11 AC_REQUIRE([gl_FUNC_ISNANL]) dnl for ISNANL_LIBM 12 13 dnl Persuade glibc <math.h> to declare ldexpl(). 14 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) 15 16 dnl Check whether it's declared. 17 dnl Mac OS X 10.3 has ldexpl() in libc but doesn't declare it in <math.h>. 18 AC_CHECK_DECL([ldexpl], , [HAVE_DECL_LDEXPL=0], [[#include <math.h>]]) 19 20 LDEXPL_LIBM= 21 if test $HAVE_DECL_LDEXPL = 1; then 22 gl_CHECK_LDEXPL_NO_LIBM 23 if test $gl_cv_func_ldexpl_no_libm = no; then 24 AC_CACHE_CHECK([whether ldexpl() can be used with libm], 25 [gl_cv_func_ldexpl_in_libm], 26 [ 27 save_LIBS="$LIBS" 28 LIBS="$LIBS -lm" 29 AC_LINK_IFELSE( 30 [AC_LANG_PROGRAM( 31 [[#include <math.h> 32 long double x;]], 33 [[return ldexpl (x, -1) > 0;]])], 34 [gl_cv_func_ldexpl_in_libm=yes], 35 [gl_cv_func_ldexpl_in_libm=no]) 36 LIBS="$save_LIBS" 37 ]) 38 if test $gl_cv_func_ldexpl_in_libm = yes; then 39 LDEXPL_LIBM=-lm 40 fi 41 fi 42 if test $gl_cv_func_ldexpl_no_libm = yes \ 43 || test $gl_cv_func_ldexpl_in_libm = yes; then 44 save_LIBS="$LIBS" 45 LIBS="$LIBS $LDEXPL_LIBM" 46 gl_FUNC_LDEXPL_WORKS 47 LIBS="$save_LIBS" 48 case "$gl_cv_func_ldexpl_works" in 49 *yes) gl_func_ldexpl=yes ;; 50 *) gl_func_ldexpl=no; REPLACE_LDEXPL=1 ;; 51 esac 52 else 53 gl_func_ldexpl=no 54 fi 55 if test $gl_func_ldexpl = yes; then 56 AC_DEFINE([HAVE_LDEXPL], [1], 57 [Define if the ldexpl() function is available.]) 58 fi 59 fi 60 if test $HAVE_DECL_LDEXPL = 0 || test $gl_func_ldexpl = no; then 61 dnl Find libraries needed to link lib/ldexpl.c. 62 if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then 63 AC_REQUIRE([gl_FUNC_LDEXP]) 64 LDEXPL_LIBM="$LDEXP_LIBM" 65 else 66 LDEXPL_LIBM="$ISNANL_LIBM" 67 fi 68 fi 69 AC_SUBST([LDEXPL_LIBM]) 70 ]) 71 72 dnl Test whether ldexpl() can be used without linking with libm. 73 dnl Set gl_cv_func_ldexpl_no_libm to 'yes' or 'no' accordingly. 74 AC_DEFUN([gl_CHECK_LDEXPL_NO_LIBM], 75 [ 76 AC_CACHE_CHECK([whether ldexpl() can be used without linking with libm], 77 [gl_cv_func_ldexpl_no_libm], 78 [ 79 AC_LINK_IFELSE( 80 [AC_LANG_PROGRAM( 81 [[#include <math.h> 82 long double x;]], 83 [[return ldexpl (x, -1) > 0;]])], 84 [gl_cv_func_ldexpl_no_libm=yes], 85 [gl_cv_func_ldexpl_no_libm=no]) 86 ]) 87 ]) 88 89 dnl Test whether ldexpl() works on finite numbers (this fails on AIX 5.1 90 dnl and Mac OS X 10.4/PowerPC). 91 AC_DEFUN([gl_FUNC_LDEXPL_WORKS], 92 [ 93 AC_REQUIRE([AC_PROG_CC]) 94 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles 95 AC_CACHE_CHECK([whether ldexpl works], [gl_cv_func_ldexpl_works], 96 [ 97 AC_RUN_IFELSE( 98 [AC_LANG_SOURCE([[ 99 #include <math.h> 100 extern 101 #ifdef __cplusplus 102 "C" 103 #endif 104 long double ldexpl (long double, int); 105 int main() 106 { 107 int result = 0; 108 { 109 volatile long double x = 1.0; 110 volatile long double y = ldexpl (x, -1); 111 if (y != 0.5L) 112 result |= 1; 113 } 114 { 115 volatile long double x = 1.73205L; 116 volatile long double y = ldexpl (x, 0); 117 if (y != x) 118 result |= 2; 119 } 120 return result; 121 }]])], 122 [gl_cv_func_ldexpl_works=yes], 123 [gl_cv_func_ldexpl_works=no], 124 [ 125 changequote(,)dnl 126 case "$host_os" in 127 aix | aix[3-6]*) gl_cv_func_ldexpl_works="guessing no";; 128 *) gl_cv_func_ldexpl_works="guessing yes";; 129 esac 130 changequote([,])dnl 131 ]) 132 ]) 133 ]) 134
