gnulib/import/m4/isnand.m4

   1 # isnand.m4 serial 11
   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 dnl Check how to get or define isnand().
   8
   9 AC_DEFUN([gl_FUNC_ISNAND],
  10 [
  11   AC_REQUIRE([gl_MATH_H_DEFAULTS])
  12   ISNAND_LIBM=
  13   gl_HAVE_ISNAND_NO_LIBM
  14   if test $gl_cv_func_isnand_no_libm = no; then
  15     gl_HAVE_ISNAND_IN_LIBM
  16     if test $gl_cv_func_isnand_in_libm = yes; then
  17       ISNAND_LIBM=-lm
  18     fi
  19   fi
  20   dnl The variable gl_func_isnand set here is used by isnan.m4.
  21   if test $gl_cv_func_isnand_no_libm = yes \
  22      || test $gl_cv_func_isnand_in_libm = yes; then
  23     gl_func_isnand=yes
  24   else
  25     gl_func_isnand=no
  26     HAVE_ISNAND=0
  27   fi
  28   AC_SUBST([ISNAND_LIBM])
  29 ])
  30
  31 dnl Check how to get or define isnand() without linking with libm.
  32
  33 AC_DEFUN([gl_FUNC_ISNAND_NO_LIBM],
  34 [
  35   gl_HAVE_ISNAND_NO_LIBM
  36   gl_func_isnand_no_libm=$gl_cv_func_isnand_no_libm
  37   if test $gl_cv_func_isnand_no_libm = yes; then
  38     AC_DEFINE([HAVE_ISNAND_IN_LIBC], [1],
  39       [Define if the isnan(double) function is available in libc.])
  40   fi
  41 ])
  42
  43 dnl Prerequisites of replacement isnand definition. It does not need -lm.
  44 AC_DEFUN([gl_PREREQ_ISNAND],
  45 [
  46   AC_REQUIRE([gl_DOUBLE_EXPONENT_LOCATION])
  47 ])
  48
  49 dnl Test whether isnand() can be used with libm.
  50
  51 AC_DEFUN([gl_HAVE_ISNAND_IN_LIBM],
  52 [
  53   AC_CACHE_CHECK([whether isnan(double) can be used with libm],
  54     [gl_cv_func_isnand_in_libm],
  55     [
  56       save_LIBS="$LIBS"
  57       LIBS="$LIBS -lm"
  58       AC_LINK_IFELSE(
  59         [AC_LANG_PROGRAM(
  60            [[#include <math.h>
  61              #if __GNUC__ >= 4
  62              # undef isnand
  63              # define isnand(x) __builtin_isnan ((double)(x))
  64              #elif defined isnan
  65              # undef isnand
  66              # define isnand(x) isnan ((double)(x))
  67              #endif
  68              double x;]],
  69            [[return isnand (x);]])],
  70         [gl_cv_func_isnand_in_libm=yes],
  71         [gl_cv_func_isnand_in_libm=no])
  72       LIBS="$save_LIBS"
  73     ])
  74 ])
  75
  76 AC_DEFUN([gl_HAVE_ISNAND_NO_LIBM],
  77 [
  78   AC_CACHE_CHECK([whether isnan(double) can be used without linking with libm],
  79     [gl_cv_func_isnand_no_libm],
  80     [
  81       AC_LINK_IFELSE(
  82         [AC_LANG_PROGRAM(
  83            [[#include <math.h>
  84              #if __GNUC__ >= 4
  85              # undef isnand
  86              # define isnand(x) __builtin_isnan ((double)(x))
  87              #else
  88              # undef isnand
  89              # define isnand(x) isnan ((double)(x))
  90              #endif
  91              double x;]],
  92            [[return isnand (x);]])],
  93         [gl_cv_func_isnand_no_libm=yes],
  94         [gl_cv_func_isnand_no_libm=no])
  95     ])
  96 ])