NAME
pthread_cancel —
cancel execution of a thread
LIBRARY
library “libpthread”
SYNOPSIS
#include
<pthread.h>
int
pthread_cancel(pthread_t
thread);
DESCRIPTION
Thepthread_cancel()
function requests that thread be canceled. The target
thread's cancelability state and type determines whether and when the target
thread reacts to the cancellation request.
- The cancelability
state of a thread
is determined by the
pthread_setcancelstate(3) function. The state can be
either:
PTHREAD_CANCEL_ENABLE: the cancelability type determines when the actual cancellation occurs. This is the default.PTHREAD_CANCEL_DISABLE: the request frompthread_cancel() remains queued until the cancellation is enabled by the thread.
- The cancellation
type of a thread
is determined by the
pthread_setcanceltype(3) function. The type can be either:
PTHREAD_CANCEL_DEFERRED: the cancellation will be delayed until the thread calls a function that is a cancellation point. This is the default. The available cancellation points are listed in pthread_setcanceltype(3).PTHREAD_CANCEL_ASYNCHRONOUS: the thread can be canceled at any time.
When the thread reacts to the cancellation request, the following occur:
- The cancellation cleanup handlers for the thread are called; see pthread_cleanup_push(3).
- When the last cancellation cleanup handler returns, the thread-specific data destructor functions will be called for the thread.
- When the last destructor function returns, the thread will be terminated; see pthread_exit(3).
The cancellation processing in the target
thread runs asynchronously with respect to the calling thread returning from
pthread_cancel().
A status of PTHREAD_CANCELED is made
available to any threads joining with the target. The symbolic constant
PTHREAD_CANCELED expands to a constant expression of
type (void *), whose value matches no pointer to an
object in memory nor the value NULL.
RETURN VALUES
If successful, the pthread_cancel()
functions will return zero. Otherwise an error number will be returned to
indicate the error.
ERRORS
The pthread_cancel() function may fail
if:
- [
ESRCH] - No thread could be found corresponding to that specified by the given thread ID.
SEE ALSO
pthread_cleanup_pop(3), pthread_join(3), pthread_testcancel(3)
STANDARDS
The function conforms to IEEE Std 1003.1-2001 (“POSIX.1”).