ulonglong.m4

来自「ALSA驱动的一些调试测试工具」· M4 代码 · 共 24 行

# ulonglong.m4 serial 4
dnl Copyright (C) 1999-2004 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 Paul Eggert.

# Define HAVE_UNSIGNED_LONG_LONG if 'unsigned long long' works.

AC_DEFUN([gl_AC_TYPE_UNSIGNED_LONG_LONG],
[
  AC_CACHE_CHECK([for unsigned long long], ac_cv_type_unsigned_long_long,
  [AC_TRY_LINK([unsigned long long ull = 1ULL; int i = 63;],
    [unsigned long long ullmax = (unsigned long long) -1;
     return ull << i | ull >> i | ullmax / ull | ullmax % ull;],
    ac_cv_type_unsigned_long_long=yes,
    ac_cv_type_unsigned_long_long=no)])
  if test $ac_cv_type_unsigned_long_long = yes; then
    AC_DEFINE(HAVE_UNSIGNED_LONG_LONG, 1,
      [Define if you have the 'unsigned long long' type.])
  fi
])