/* Copyright (C) 2002, 2003 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include <errno.h> #include "pthreadP.h" #include <atomic.h> int attribute_protected __pthread_setcancelstate ( int state, int *oldstate) { volatile struct pthread *self; if (state < PTHREAD_CANCEL_ENABLE || state > PTHREAD_CANCEL_DISABLE) return EINVAL; self = THREAD_SELF; int oldval = THREAD_GETMEM (self, cancelhandling); while (1) { int newval = (state == PTHREAD_CANCEL_DISABLE ? oldval | CANCELSTATE_BITMASK : oldval & ~CANCELSTATE_BITMASK); /* Store the old value. */ if (oldstate != NULL) *oldstate = ((oldval & CANCELSTATE_BITMASK) ? PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE); /* Avoid doing unnecessary work. The atomic operation can potentially be expensive if the memory has to be locked and remote cache lines have to be invalidated. */ if (oldval == newval) break; /* Update the cancel handling word. This has to be done atomically since other bits could be modified as well. */ int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, oldval); if (__builtin_expect (curval == oldval, 1)) { if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval)) __do_cancel (); break; } /* Prepare for the next round. */ oldval = curval; } return 0; } strong_alias (__pthread_setcancelstate, pthread_setcancelstate)