git.m6w6.name Git - awesomized/libmemcached/blob - m4/pandora_stack_direction.m4

   1 dnl  Copyright (C) 2009 Sun Microsystems
   2 dnl This file is free software; Sun Microsystems
   3 dnl gives unlimited permission to copy and/or distribute it,
   4 dnl with or without modifications, as long as this notice is preserved.
   5
   6 #--------------------------------------------------------------------
   7 # Check what direction the stack runs in
   8 #--------------------------------------------------------------------
   9
  10 AC_DEFUN([PANDORA_STACK_DIRECTION],[
  11  AC_REQUIRE([AC_FUNC_ALLOCA])
  12  AC_CACHE_CHECK([stack direction], [ac_cv_c_stack_direction],[
  13   AC_RUN_IFELSE([AC_LANG_PROGRAM([[
  14 #include <stdlib.h>
  15  int find_stack_direction ()
  16  {
  17    static char *addr = 0;
  18    auto char dummy;
  19    if (addr == 0)
  20      {
  21        addr = &dummy;
  22        return find_stack_direction ();
  23      }
  24    else
  25      return (&dummy > addr) ? 1 : -1;
  26  }
  27   ]],[[
  28     exit (find_stack_direction() < 0);
  29   ]])],[
  30    ac_cv_c_stack_direction=1
  31   ],[
  32    ac_cv_c_stack_direction=-1
  33   ])
  34  ])
  35  AC_DEFINE_UNQUOTED(STACK_DIRECTION, $ac_cv_c_stack_direction)
  36 ])
  37
  38
  39