# isnand.m4 serial 11

dnl Copyright (C) 2007-2018 Free Software Foundation, Inc.

dnl This file is free software; the Free Software Foundation

dnl gives unlimited permission to copy and/or distribute it,

dnl with or without modifications, as long as this notice is preserved.

dnl Check how to get or define isnand().

AC_DEFUN([gl_FUNC_ISNAND],

[

  AC_REQUIRE([gl_MATH_H_DEFAULTS])

  ISNAND_LIBM=

  gl_HAVE_ISNAND_NO_LIBM

  if test $gl_cv_func_isnand_no_libm = no; then

    gl_HAVE_ISNAND_IN_LIBM

    if test $gl_cv_func_isnand_in_libm = yes; then

      ISNAND_LIBM=-lm

    fi

  fi

  dnl The variable gl_func_isnand set here is used by isnan.m4.

  if test $gl_cv_func_isnand_no_libm = yes \

     || test $gl_cv_func_isnand_in_libm = yes; then

    gl_func_isnand=yes

  else

    gl_func_isnand=no

    HAVE_ISNAND=0

  fi

  AC_SUBST([ISNAND_LIBM])

])

dnl Check how to get or define isnand() without linking with libm.

AC_DEFUN([gl_FUNC_ISNAND_NO_LIBM],

[

  gl_HAVE_ISNAND_NO_LIBM

  gl_func_isnand_no_libm=$gl_cv_func_isnand_no_libm

  if test $gl_cv_func_isnand_no_libm = yes; then

    AC_DEFINE([HAVE_ISNAND_IN_LIBC], [1],

      [Define if the isnan(double) function is available in libc.])

  fi

])

dnl Prerequisites of replacement isnand definition. It does not need -lm.

AC_DEFUN([gl_PREREQ_ISNAND],

[

  AC_REQUIRE([gl_DOUBLE_EXPONENT_LOCATION])

])

dnl Test whether isnand() can be used with libm.

AC_DEFUN([gl_HAVE_ISNAND_IN_LIBM],

[

  AC_CACHE_CHECK([whether isnan(double) can be used with libm],

    [gl_cv_func_isnand_in_libm],

    [

      save_LIBS="$LIBS"

      LIBS="$LIBS -lm"

      AC_LINK_IFELSE(

        [AC_LANG_PROGRAM(

           [[#include <math.h>

             #if __GNUC__ >= 4

             # undef isnand

             # define isnand(x) __builtin_isnan ((double)(x))

             #elif defined isnan

             # undef isnand

             # define isnand(x) isnan ((double)(x))

             #endif

             double x;]],

           [[return isnand (x);]])],

        [gl_cv_func_isnand_in_libm=yes],

        [gl_cv_func_isnand_in_libm=no])

      LIBS="$save_LIBS"

    ])

])

AC_DEFUN([gl_HAVE_ISNAND_NO_LIBM],

[

  AC_CACHE_CHECK([whether isnan(double) can be used without linking with libm],

    [gl_cv_func_isnand_no_libm],

    [

      AC_LINK_IFELSE(

        [AC_LANG_PROGRAM(

           [[#include <math.h>

             #if __GNUC__ >= 4

             # undef isnand

             # define isnand(x) __builtin_isnan ((double)(x))

             #else

             # undef isnand

             # define isnand(x) isnan ((double)(x))

             #endif

             double x;]],

           [[return isnand (x);]])],

        [gl_cv_func_isnand_no_libm=yes],

        [gl_cv_func_isnand_no_libm=no])

    ])

])