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/* Copyright (C) 2002-2021 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, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include "pthreadP.h"
#include <atomic.h>
int
__pthread_setcanceltype (int type, int *oldtype)
{
if (type < PTHREAD_CANCEL_DEFERRED || type > PTHREAD_CANCEL_ASYNCHRONOUS)
return EINVAL;
volatile struct pthread *self = THREAD_SELF;
int oldval = THREAD_GETMEM (self, cancelhandling);
while (1)
{
int newval = (type == PTHREAD_CANCEL_ASYNCHRONOUS
? oldval | CANCELTYPE_BITMASK
: oldval & ~CANCELTYPE_BITMASK);
/* Store the old value. */
if (oldtype != NULL)
*oldtype = ((oldval & CANCELTYPE_BITMASK)
? PTHREAD_CANCEL_ASYNCHRONOUS : PTHREAD_CANCEL_DEFERRED);
/* 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 (__glibc_likely (curval == oldval))
{
if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
{
THREAD_SETMEM (self, result, PTHREAD_CANCELED);
__do_cancel ();
}
break;
}
/* Prepare for the next round. */
oldval = curval;
}
return 0;
}
libc_hidden_def (__pthread_setcanceltype)
weak_alias (__pthread_setcanceltype, pthread_setcanceltype)
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