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pthread_detach(3p) [centos man page]

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

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing 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 effect of multiple pthread_detach() calls on the same target thread is unspecified. 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 fail if: EINVAL The implementation has detected that the value specified by thread does not refer to a joinable thread. ESRCH No thread could be found corresponding to that specified by the given thread ID. 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). FUTURE DIRECTIONS
None. SEE ALSO
pthread_join(), the Base Definitions volume of IEEE Std 1003.1-2001, <pthread.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 . IEEE
/The Open Group 2003 PTHREAD_DETACH(3P)

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PTHREAD_DETACH(3)					     Linux Programmer's Manual						 PTHREAD_DETACH(3)

NAME
pthread_detach - detach a thread SYNOPSIS
#include <pthread.h> int pthread_detach(pthread_t thread); Compile and link with -pthread. DESCRIPTION
The pthread_detach() function marks the thread identified by thread as detached. When a detached thread terminates, its resources are automatically released back to the system without the need for another thread to join with the terminated thread. Attempting to detach an already detached thread results in unspecified behavior. RETURN VALUE
On success, pthread_detach() returns 0; on error, it returns an error number. ERRORS
EINVAL thread is not a joinable thread. ESRCH No thread with the ID thread could be found. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +-----------------+---------------+---------+ |Interface | Attribute | Value | +-----------------+---------------+---------+ |pthread_detach() | Thread safety | MT-Safe | +-----------------+---------------+---------+ CONFORMING TO
POSIX.1-2001, POSIX.1-2008. NOTES
Once a thread has been detached, it can't be joined with pthread_join(3) or be made joinable again. A new thread can be created in a detached state using pthread_attr_setdetachstate(3) to set the detached attribute of the attr argument of pthread_create(3). The detached attribute merely determines the behavior of the system when the thread terminates; it does not prevent the thread from being terminated if the process terminates using exit(3) (or equivalently, if the main thread returns). Either pthread_join(3) or pthread_detach() should be called for each thread that an application creates, so that system resources for the thread can be released. (But note that the resources of any threads for which one of these actions has not been done will be freed when the process terminates.) EXAMPLE
The following statement detaches the calling thread: pthread_detach(pthread_self()); SEE ALSO
pthread_attr_setdetachstate(3), pthread_cancel(3), pthread_create(3), pthread_exit(3), pthread_join(3), pthreads(7) COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. Linux 2017-09-15 PTHREAD_DETACH(3)
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