/*********************************************************************** * * * This software is part of the ast package * * Copyright (c) 1985-2007 AT&T Knowledge Ventures * * and is licensed under the * * Common Public License, Version 1.0 * * by AT&T Knowledge Ventures * * * * 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" /* Obtain/release exclusive use of a stream. ** ** Written by Kiem-Phong Vo. */ /* the main locking/unlocking interface */ #if __STD_C int sfmutex(Sfio_t* f, int type) #else int sfmutex(f, type) Sfio_t* f; int type; #endif { #if !vt_threaded NOTUSED(f); NOTUSED(type); return 0; #else SFONCE(); if(!f) return -1; if(!f->mutex) { if(f->bits&SF_PRIVATE) return 0; vtmtxlock(_Sfmutex); f->mutex = vtmtxopen(NIL(Vtmutex_t*), VT_INIT); vtmtxunlock(_Sfmutex); if(!f->mutex) return -1; } if(type == SFMTX_LOCK) return vtmtxlock(f->mutex); else if(type == SFMTX_TRYLOCK) return vtmtxtrylock(f->mutex); else if(type == SFMTX_UNLOCK) return vtmtxunlock(f->mutex); else if(type == SFMTX_CLRLOCK) return vtmtxclrlock(f->mutex); else return -1; #endif /*vt_threaded*/ }