longlong.m4

来自「linux下MPEG播放器」· M4 代码 · 共 26 行

# longlong.m4 serial 4
dnl Copyright (C) 1999-2003 Free Software Foundation, Inc.
dnl This file is free software, distributed under the terms of the GNU
dnl General Public License.  As a special exception to the GNU General
dnl Public License, this file may be distributed as part of a program
dnl that contains a configuration script generated by Autoconf, under
dnl the same distribution terms as the rest of that program.

dnl From Paul Eggert.

# Define HAVE_LONG_LONG if 'long long' works.

AC_DEFUN([jm_AC_TYPE_LONG_LONG],
[
  AC_CACHE_CHECK([for long long], ac_cv_type_long_long,
  [AC_TRY_LINK([long long ll = 1LL; int i = 63;],
    [long long llmax = (long long) -1;
     return ll << i | ll >> i | llmax / ll | llmax % ll;],
    ac_cv_type_long_long=yes,
    ac_cv_type_long_long=no)])
  if test $ac_cv_type_long_long = yes; then
    AC_DEFINE(HAVE_LONG_LONG, 1,
      [Define if you have the 'long long' type.])
  fi
])