gnulib/import/m4/frexpl.m4

   1 # frexpl.m4 serial 20
   2 dnl Copyright (C) 2007-2016 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_FREXPL],
   8 [
   9   AC_REQUIRE([gl_MATH_H_DEFAULTS])
  10   AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
  11
  12   dnl Persuade glibc <math.h> to declare frexpl().
  13   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
  14
  15   dnl Check whether it's declared.
  16   dnl Mac OS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
  17   AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [[#include <math.h>]])
  18
  19   FREXPL_LIBM=
  20   if test $HAVE_DECL_FREXPL = 1; then
  21     gl_CHECK_FREXPL_NO_LIBM
  22     if test $gl_cv_func_frexpl_no_libm = no; then
  23       AC_CACHE_CHECK([whether frexpl() can be used with libm],
  24         [gl_cv_func_frexpl_in_libm],
  25         [
  26           save_LIBS="$LIBS"
  27           LIBS="$LIBS -lm"
  28           AC_LINK_IFELSE(
  29             [AC_LANG_PROGRAM(
  30                [[#include <math.h>
  31                  long double x;]],
  32                [[int e; return frexpl (x, &e) > 0;]])],
  33             [gl_cv_func_frexpl_in_libm=yes],
  34             [gl_cv_func_frexpl_in_libm=no])
  35           LIBS="$save_LIBS"
  36         ])
  37       if test $gl_cv_func_frexpl_in_libm = yes; then
  38         FREXPL_LIBM=-lm
  39       fi
  40     fi
  41     if test $gl_cv_func_frexpl_no_libm = yes \
  42        || test $gl_cv_func_frexpl_in_libm = yes; then
  43       save_LIBS="$LIBS"
  44       LIBS="$LIBS $FREXPL_LIBM"
  45       gl_FUNC_FREXPL_WORKS
  46       LIBS="$save_LIBS"
  47       case "$gl_cv_func_frexpl_works" in
  48         *yes) gl_func_frexpl=yes ;;
  49         *)    gl_func_frexpl=no; REPLACE_FREXPL=1 ;;
  50       esac
  51     else
  52       gl_func_frexpl=no
  53     fi
  54     if test $gl_func_frexpl = yes; then
  55       AC_DEFINE([HAVE_FREXPL], [1],
  56         [Define if the frexpl() function is available.])
  57     fi
  58   fi
  59   if test $HAVE_DECL_FREXPL = 0 || test $gl_func_frexpl = no; then
  60     dnl Find libraries needed to link lib/frexpl.c.
  61     if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
  62       AC_REQUIRE([gl_FUNC_FREXP])
  63       FREXPL_LIBM="$FREXP_LIBM"
  64     else
  65       FREXPL_LIBM=
  66     fi
  67   fi
  68   AC_SUBST([FREXPL_LIBM])
  69 ])
  70
  71 AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
  72 [
  73   AC_REQUIRE([gl_MATH_H_DEFAULTS])
  74   AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
  75   dnl Check whether it's declared.
  76   dnl Mac OS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
  77   AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [[#include <math.h>]])
  78   if test $HAVE_DECL_FREXPL = 1; then
  79     gl_CHECK_FREXPL_NO_LIBM
  80     if test $gl_cv_func_frexpl_no_libm = yes; then
  81       gl_FUNC_FREXPL_WORKS
  82       case "$gl_cv_func_frexpl_works" in
  83         *yes) gl_func_frexpl_no_libm=yes ;;
  84         *)    gl_func_frexpl_no_libm=no; REPLACE_FREXPL=1 ;;
  85       esac
  86     else
  87       gl_func_frexpl_no_libm=no
  88       dnl Set REPLACE_FREXPL here because the system may have frexpl in libm.
  89       REPLACE_FREXPL=1
  90     fi
  91     if test $gl_func_frexpl_no_libm = yes; then
  92       AC_DEFINE([HAVE_FREXPL_IN_LIBC], [1],
  93         [Define if the frexpl() function is available in libc.])
  94     fi
  95   fi
  96 ])
  97
  98 dnl Test whether frexpl() can be used without linking with libm.
  99 dnl Set gl_cv_func_frexpl_no_libm to 'yes' or 'no' accordingly.
 100 AC_DEFUN([gl_CHECK_FREXPL_NO_LIBM],
 101 [
 102   AC_CACHE_CHECK([whether frexpl() can be used without linking with libm],
 103     [gl_cv_func_frexpl_no_libm],
 104     [
 105       AC_LINK_IFELSE(
 106         [AC_LANG_PROGRAM(
 107            [[#include <math.h>
 108              long double x;]],
 109            [[int e; return frexpl (x, &e) > 0;]])],
 110         [gl_cv_func_frexpl_no_libm=yes],
 111         [gl_cv_func_frexpl_no_libm=no])
 112     ])
 113 ])
 114
 115 dnl Test whether frexpl() works on finite numbers (this fails on
 116 dnl Mac OS X 10.4/PowerPC, on AIX 5.1, and on BeOS), on denormalized numbers
 117 dnl (this fails on Mac OS X 10.5/i386), and also on infinite numbers (this
 118 dnl fails e.g. on IRIX 6.5 and mingw).
 119 AC_DEFUN([gl_FUNC_FREXPL_WORKS],
 120 [
 121   AC_REQUIRE([AC_PROG_CC])
 122   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
 123   AC_CACHE_CHECK([whether frexpl works], [gl_cv_func_frexpl_works],
 124     [
 125       AC_RUN_IFELSE(
 126         [AC_LANG_SOURCE([[
 127 #include <float.h>
 128 #include <math.h>
 129 /* Override the values of <float.h>, like done in float.in.h.  */
 130 #if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
 131 # undef LDBL_MIN_EXP
 132 # define LDBL_MIN_EXP    (-16381)
 133 #endif
 134 #if defined __i386__ && defined __FreeBSD__
 135 # undef LDBL_MIN_EXP
 136 # define LDBL_MIN_EXP    (-16381)
 137 #endif
 138 #if (defined _ARCH_PPC || defined _POWER) && defined _AIX && (LDBL_MANT_DIG == 106) && defined __GNUC__
 139 # undef LDBL_MIN_EXP
 140 # define LDBL_MIN_EXP DBL_MIN_EXP
 141 #endif
 142 #if defined __sgi && (LDBL_MANT_DIG >= 106)
 143 # if defined __GNUC__
 144 #  undef LDBL_MIN_EXP
 145 #  define LDBL_MIN_EXP DBL_MIN_EXP
 146 # endif
 147 #endif
 148 extern
 149 #ifdef __cplusplus
 150 "C"
 151 #endif
 152 long double frexpl (long double, int *);
 153 int main()
 154 {
 155   int result = 0;
 156   volatile long double x;
 157   /* Test on finite numbers that fails on AIX 5.1.  */
 158   x = 16.0L;
 159   {
 160     int exp = -9999;
 161     frexpl (x, &exp);
 162     if (exp != 5)
 163       result |= 1;
 164   }
 165   /* Test on finite numbers that fails on Mac OS X 10.4, because its frexpl
 166      function returns an invalid (incorrectly normalized) value: it returns
 167                y = { 0x3fe028f5, 0xc28f5c28, 0x3c9eb851, 0xeb851eb8 }
 168      but the correct result is
 169           0.505L = { 0x3fe028f5, 0xc28f5c29, 0xbc547ae1, 0x47ae1480 }  */
 170   x = 1.01L;
 171   {
 172     int exp = -9999;
 173     long double y = frexpl (x, &exp);
 174     if (!(exp == 1 && y == 0.505L))
 175       result |= 2;
 176   }
 177   /* Test on large finite numbers.  This fails on BeOS at i = 16322, while
 178      LDBL_MAX_EXP = 16384.
 179      In the loop end test, we test x against Infinity, rather than comparing
 180      i with LDBL_MAX_EXP, because BeOS <float.h> has a wrong LDBL_MAX_EXP.  */
 181   {
 182     int i;
 183     for (i = 1, x = 1.0L; x != x + x; i++, x *= 2.0L)
 184       {
 185         int exp = -9999;
 186         frexpl (x, &exp);
 187         if (exp != i)
 188           {
 189             result |= 4;
 190             break;
 191           }
 192       }
 193   }
 194   /* Test on denormalized numbers.  */
 195   {
 196     int i;
 197     for (i = 1, x = 1.0L; i >= LDBL_MIN_EXP; i--, x *= 0.5L)
 198       ;
 199     if (x > 0.0L)
 200       {
 201         int exp;
 202         long double y = frexpl (x, &exp);
 203         /* On machines with IEEE854 arithmetic: x = 1.68105e-4932,
 204            exp = -16382, y = 0.5.  On Mac OS X 10.5: exp = -16384, y = 0.5.  */
 205         if (exp != LDBL_MIN_EXP - 1)
 206           result |= 8;
 207       }
 208   }
 209   /* Test on infinite numbers.  */
 210   x = 1.0L / 0.0L;
 211   {
 212     int exp;
 213     long double y = frexpl (x, &exp);
 214     if (y != x)
 215       result |= 16;
 216   }
 217   return result;
 218 }]])],
 219         [gl_cv_func_frexpl_works=yes],
 220         [gl_cv_func_frexpl_works=no],
 221         [
 222 changequote(,)dnl
 223          case "$host_os" in
 224            aix | aix[3-6]* | beos* | darwin* | irix* | mingw* | pw*)
 225               gl_cv_func_frexpl_works="guessing no";;
 226            *) gl_cv_func_frexpl_works="guessing yes";;
 227          esac
 228 changequote([,])dnl
 229         ])
 230     ])
 231 ])