PTHREAD_CANCEL(3)					   BSD Library Functions Manual 					 PTHREAD_CANCEL(3)

NAME

     pthread_cancel -- cancel execution of a thread

LIBRARY

     POSIX Threads Library (libpthread, -lpthread)

SYNOPSIS

     #include <pthread.h>

     int
     pthread_cancel(pthread_t thread);

DESCRIPTION

     The pthread_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.

       1.   The cancelability state of a thread is determined by the pthread_setcancelstate(3) function.  The state can be either:

	      o   PTHREAD_CANCEL_ENABLE: the cancelability type determines when the actual cancellation occurs.  This is the default.

	      o   PTHREAD_CANCEL_DISABLE: the request from pthread_cancel() remains queued until the cancellation is enabled by the thread.

       2.   The cancellation type of a thread is determined by the pthread_setcanceltype(3) function.  The type can be either:

	      o   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).

	      o   PTHREAD_CANCEL_ASYNCHRONOUS: the thread can be canceled at any time.

     When the tread reacts to the cancellation request, the following occur:

       1.   The cancellation cleanup handlers for the thread are called; see pthread_cleanup_push(3).

       2.   When the last cancellation cleanup handler returns, the thread-specific data destructor functions will be called for the thread.

       3.   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'').

BSD
								   July 9, 2010 							       BSD