portable/src/PStackSize.c

/*---------------------------------------------------------------------------*
 *  PStackSize.c  *
 *                                                                           *
 *  Copyright 2007, 2008 Nuance Communciations, Inc.                               *
 *                                                                           *
 *  Licensed under the Apache License, Version 2.0 (the 'License');          *
 *  you may not use this file except in compliance with the License.         *
 *                                                                           *
 *  You may obtain a copy of the License at                                  *
 *      http://www.apache.org/licenses/LICENSE-2.0                           *
 *                                                                           *
 *  Unless required by applicable law or agreed to in writing, software      *
 *  distributed under the License is distributed on an 'AS IS' BASIS,        *
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * 
 *  See the License for the specific language governing permissions and      *
 *  limitations under the License.                                           *
 *                                                                           *
 *---------------------------------------------------------------------------*/

#include "pstdio.h"
#include "PStackSize.h"

#ifdef _WIN32

static const char * PSTACK_BASE = NULL;

/** Initialize the stack base.  This should be done in the main() function.
 * Note that the local variables of main() are not taken into account in the
 * stack size computation.  To overcome this problem, rewrite main() as a
 * simple function that first invokes PSTACK_SIZE_INIT and then invokes the
 * original main().
*/
void PSTACK_SIZE_INIT()
{
  PSTACK_BASE = (const char *) _alloca(0);
}

/**
 * Computes the current stack size.  The returned value is the number of bytes
 * in the stack.
 **/
size_t PSTACK_SIZE_GET()
{
  return (PSTACK_BASE - ((const char *) _alloca(0)));
}

#else

/* Insert other platform implementations here... */
/*
#error not supported at this time
*/
void PSTACK_SIZE_INIT()
{}

size_t PSTACK_SIZE_GET()
{
  return 0;
}

#endif