vararrays.m4

来自「制作2.6内核的CLFS时 使用的diffutils-2.8.7.tar.gz包」· M4 代码 · 共 38 行

# Check for variable-length arrays.

#serial 1

# From Paul Eggert

# Copyright (C) 2001 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.

AC_DEFUN([AC_C_VARARRAYS],
[
  AC_CACHE_CHECK([for variable-length arrays],
    ac_cv_c_vararrays,
    [AC_TRY_COMPILE(
       [],
       [static int x; char a[++x]; a[sizeof a - 1] = 0; return a[0];],
       ac_cv_c_vararrays=yes,
       ac_cv_c_vararrays=no)])
  if test $ac_cv_c_vararrays = yes; then
    AC_DEFINE(HAVE_C_VARARRAYS, 1,
      [Define to 1 if C supports variable-length arrays.])
  fi
])