longdouble.m4

来自「这是一个嵌入式linux系统下的BT下载工具包」· M4 代码 · 共 32 行

# longdouble.m4 serial 2 (gettext-0.15)
dnl Copyright (C) 2002-2003, 2006 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 From Bruno Haible.
dnl Test whether the compiler supports the 'long double' type.
dnl Prerequisite: AC_PROG_CC

dnl This file is only needed in autoconf <= 2.59.  Newer versions of autoconf
dnl have a macro AC_TYPE_LONG_DOUBLE with identical semantics.

AC_DEFUN([gt_TYPE_LONGDOUBLE],
[
  AC_CACHE_CHECK([for long double], gt_cv_c_long_double,
    [if test "$GCC" = yes; then
       gt_cv_c_long_double=yes
     else
       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];
         ], ,
         gt_cv_c_long_double=yes, gt_cv_c_long_double=no)
     fi])
  if test $gt_cv_c_long_double = yes; then
    AC_DEFINE(HAVE_LONG_DOUBLE, 1, [Define if you have the 'long double' type.])
  fi
])