PTHREAD_CANCEL(3P)        POSIX Programmer's Manual       PTHREAD_CANCEL(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       pthread_cancel — cancel execution of a thread

SYNOPSIS         top

       #include <pthread.h>

       int pthread_cancel(pthread_t thread);

DESCRIPTION         top

       The pthread_cancel() function shall request that thread be canceled.
       The target thread's cancelability state and type determines when the
       cancellation takes effect. When the cancellation is acted on, the
       cancellation cleanup handlers for thread shall be called. When the
       last cancellation cleanup handler returns, the thread-specific data
       destructor functions shall be called for thread.  When the last
       destructor function returns, thread shall be terminated.

       The cancellation processing in the target thread shall run
       asynchronously with respect to the calling thread returning from

RETURN VALUE         top

       If successful, the pthread_cancel() function shall return zero;
       otherwise, an error number shall be returned to indicate the error.

ERRORS         top

       The pthread_cancel() function shall not return an error code of

       The following sections are informative.

EXAMPLES         top




RATIONALE         top

       Two alternative functions were considered for sending the
       cancellation notification to a thread. One would be to define a new
       SIGCANCEL signal that had the cancellation semantics when delivered;
       the other was to define the new pthread_cancel() function, which
       would trigger the cancellation semantics.

       The advantage of a new signal was that so much of the delivery
       criteria were identical to that used when trying to deliver a signal
       that making cancellation notification a signal was seen as
       consistent. Indeed, many implementations implement cancellation using
       a special signal. On the other hand, there would be no signal
       functions that could be used with this signal except pthread_kill(),
       and the behavior of the delivered cancellation signal would be unlike
       any previously existing defined signal.

       The benefits of a special function include the recognition that this
       signal would be defined because of the similar delivery criteria and
       that this is the only common behavior between a cancellation request
       and a signal. In addition, the cancellation delivery mechanism does
       not have to be implemented as a signal. There are also strong, if not
       stronger, parallels with language exception mechanisms than with
       signals that are potentially obscured if the delivery mechanism is
       visibly closer to signals.

       In the end, it was considered that as there were so many exceptions
       to the use of the new signal with existing signals functions it would
       be misleading. A special function has resolved this problem.  This
       function was carefully defined so that an implementation wishing to
       provide the cancellation functions on top of signals could do so.
       The special function also means that implementations are not obliged
       to implement cancellation with signals.

       If an implementation detects use of a thread ID after the end of its
       lifetime, it is recommended that the function should fail and report
       an [ESRCH] error.



SEE ALSO         top

       pthread_exit(3p), pthread_cond_timedwait(3p), pthread_join(3p),

       The Base Definitions volume of POSIX.1‐2008, pthread.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) In the event of any discrepancy between this version and
       the original IEEE and The Open Group Standard, the original IEEE and
       The Open Group Standard is the referee document. The original
       Standard can be obtained online at .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see .

IEEE/The Open Group                 2013                  PTHREAD_CANCEL(3P)