PTHREAD_DETACH
Section: POSIX Programmer's Manual (3P)
Updated: 2017
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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
pthread_detach
--- detach a thread
SYNOPSIS
#include <pthread.h>
int pthread_detach(pthread_t thread);
DESCRIPTION
The
pthread_detach()
function shall indicate to the implementation that storage for the
thread
thread
can be reclaimed when that thread terminates. If
thread
has not terminated,
pthread_detach()
shall not cause it to terminate.
The behavior is undefined if the value specified by the
thread
argument to
pthread_detach()
does not refer to a joinable thread.
RETURN VALUE
If the call succeeds,
pthread_detach()
shall return 0; otherwise, an error number shall be returned to
indicate the error.
ERRORS
The
pthread_detach()
function shall not return an error code of
[EINTR].
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
The
pthread_join()
or
pthread_detach()
functions should eventually be called for every thread that is created
so that storage associated with the thread may be reclaimed.
It has been suggested that a ``detach'' function is not necessary; the
detachstate
thread creation attribute is sufficient, since a thread need never be
dynamically detached. However, need arises in at least two cases:
- 1.
-
In a cancellation handler for a
pthread_join()
it is nearly essential to have a
pthread_detach()
function in order to detach the thread on which
pthread_join()
was waiting. Without it, it would be necessary to have the handler do
another
pthread_join()
to attempt to detach the thread, which would both delay the cancellation
processing for an unbounded period and introduce a new call to
pthread_join(),
which might itself need a cancellation handler. A dynamic detach is
nearly essential in this case.
- 2.
-
In order to detach the ``initial thread'' (as may be desirable in
processes that set up server threads).
If an implementation detects that the value specified by the
thread
argument to
pthread_detach()
does not refer to a joinable thread, it is recommended that the
function should fail and report an
[EINVAL]
error.
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.
FUTURE DIRECTIONS
None.
SEE ALSO
pthread_join()
The Base Definitions volume of POSIX.1-2017,
<pthread.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
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
http://www.opengroup.org/unix/online.html .
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
https://www.kernel.org/doc/man-pages/reporting_bugs.html .