optctx.c revision 7c2fbfb345896881c631598ee3852ce9ce33fb07
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2008 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Glenn Fowler
* AT&T Research
*
* _opt_infop_ context control
*
* allocate new context:
* new_context = optctx(0, 0);
* free new context:
* optctx(0, new_context);
* switch to new_context:
* old_context = optctx(new_context, 0);
* switch to old_context and free new_context:
* optctx(old_context, new_context);
*/
#include <optlib.h>
static Opt_t* freecontext;
{
if (o)
{
if (freecontext)
free(o);
else
freecontext = o;
if (!p)
return 0;
}
if (p)
{
o = _opt_infop_;
_opt_infop_ = p;
}
else
{
if (o = freecontext)
freecontext = 0;
return 0;
}
return o;
}