stak.h

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C头文件 代码 · 共 115 行

/* @(#)stak.h	4.1      7/17/90 */

/************************************************************************
 *									*
 *			Copyright (c) 1986 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/
/*
 *
 *   Modification History:
 *
 * 001 - Gary Gaudet for Andy Gadsby 09-mar-88
 *	i18n version of csh
 *
 *
 *
 */

/*
 *	UNIX shell
 *
 *	Bell Telephone Laboratories
 *
 */

/* To use stack as temporary workspace across
 * possible storage allocation (eg name lookup)
 * a) get ptr from `relstak'
 * b) can now use `pushstak'
 * c) then reset with `setstak'
 * d) `absstak' gives real address if needed
 */
#define		relstak()	(staktop-stakbot)
#define		absstak(x)	(stakbot+Rcheat(x))
#define		setstak(x)	(staktop=absstak(x))
#define		pushstak(c)	(*staktop++=(c))
#define		zerostak()	(*staktop=0)

/* Used to address an item left on the top of
 * the stack (very temporary)
 */
#define		curstak()	(staktop)

/* `usestak' before `pushstak' then `fixstak'
 * These routines are safe against heap
 * being allocated.
 */
#define		usestak()	{locstak();}

/* for local use only since it hands
 * out a real address for the stack top
 */
extern CHTYPE		*locstak();

/* Will allocate the item being used and return its
 * address (safe now).
 */
#define		fixstak()	endstak(staktop)

/* For use after `locstak' to hand back
 * new stack top and then allocate item
 */
extern CHTYPE		*endstak();

/* Copy a string onto the stack and
 * allocate the space.
 */
extern CHTYPE		*cpystak();

/* Allocate given ammount of stack space */
extern CHTYPE		*getstak();

/* A chain of ptrs of stack blocks that
 * have become covered by heap allocation.
 * `tdystak' will return them to the heap.
 */
extern struct blk	*stakbsy;

/* Base of the entire stack */
extern CHTYPE		*stakbas;

/* Top of entire stack */
extern CHTYPE		*brkend;

/* Base of current item */
extern CHTYPE		*stakbot;

/* Top of current item */
extern CHTYPE		*staktop;

/* Used with tdystak */
extern CHTYPE		*savstak();