sfclrlock.c revision 1
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2011 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 *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (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> *
* *
***********************************************************************/
#include "sfhdr.h"
/* Function to clear a locked stream.
** This is useful for programs that longjmp from the mid of an sfio function.
** There is no guarantee on data integrity in such a case.
**
** Written by Kiem-Phong Vo
*/
#if __STD_C
int sfclrlock(Sfio_t* f)
#else
int sfclrlock(f)
Sfio_t *f;
#endif
{
int rv;
SFMTXDECL(f);
/* already closed */
if(f && (f->mode&SF_AVAIL))
return 0;
SFMTXENTER(f,0);
/* clear error bits */
f->flags &= ~(SF_ERROR|SF_EOF);
/* clear peek locks */
if(f->mode&SF_PKRD)
{ f->here -= f->endb-f->next;
f->endb = f->next;
}
SFCLRBITS(f);
/* throw away all lock bits except for stacking state SF_PUSH */
f->mode &= (SF_RDWR|SF_INIT|SF_POOL|SF_PUSH|SF_SYNCED|SF_STDIO);
rv = (f->mode&SF_PUSH) ? 0 : (f->flags&SF_FLAGS);
SFMTXRETURN(f, rv);
}