226 lines
5.3 KiB
HTML
226 lines
5.3 KiB
HTML
|
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<HTML><HEAD><TITLE>Man page of PTHREAD_JOIN</TITLE>
|
|
</HEAD><BODY>
|
|
<H1>PTHREAD_JOIN</H1>
|
|
Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<BR><A HREF="#index">Index</A>
|
|
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
|
|
|
|
<A NAME="lbAB"> </A>
|
|
<H2>NAME</H2>
|
|
|
|
pthread_join - join with a terminated thread
|
|
<A NAME="lbAC"> </A>
|
|
<H2>SYNOPSIS</H2>
|
|
|
|
<PRE>
|
|
<B>#include <<A HREF="file:///usr/include/pthread.h">pthread.h</A>></B>
|
|
|
|
<B>int pthread_join(pthread_t </B><I>thread</I><B>, void **</B><I>retval</I><B>);</B>
|
|
</PRE>
|
|
|
|
<P>
|
|
|
|
Compile and link with <I>-pthread</I>.
|
|
<A NAME="lbAD"> </A>
|
|
<H2>DESCRIPTION</H2>
|
|
|
|
The
|
|
<B>pthread_join</B>()
|
|
|
|
function waits for the thread specified by
|
|
<I>thread</I>
|
|
|
|
to terminate.
|
|
If that thread has already terminated, then
|
|
<B>pthread_join</B>()
|
|
|
|
returns immediately.
|
|
The thread specified by
|
|
<I>thread</I>
|
|
|
|
must be joinable.
|
|
<P>
|
|
|
|
If
|
|
<I>retval</I>
|
|
|
|
is not NULL, then
|
|
<B>pthread_join</B>()
|
|
|
|
copies the exit status of the target thread
|
|
(i.e., the value that the target thread supplied to
|
|
<B><A HREF="/cgi-bin/man/man2html?3+pthread_exit">pthread_exit</A></B>(3))
|
|
|
|
into the location pointed to by
|
|
<I>retval</I>.
|
|
|
|
If the target thread was canceled, then
|
|
<B>PTHREAD_CANCELED</B>
|
|
|
|
is placed in the location pointed to by
|
|
<I>retval</I>.
|
|
|
|
<P>
|
|
|
|
If multiple threads simultaneously try to join with the same thread,
|
|
the results are undefined.
|
|
If the thread calling
|
|
<B>pthread_join</B>()
|
|
|
|
is canceled, then the target thread will remain joinable
|
|
(i.e., it will not be detached).
|
|
<A NAME="lbAE"> </A>
|
|
<H2>RETURN VALUE</H2>
|
|
|
|
On success,
|
|
<B>pthread_join</B>()
|
|
|
|
returns 0;
|
|
on error, it returns an error number.
|
|
<A NAME="lbAF"> </A>
|
|
<H2>ERRORS</H2>
|
|
|
|
<DL COMPACT>
|
|
<DT id="1"><B>EDEADLK</B>
|
|
|
|
<DD>
|
|
A deadlock was detected
|
|
|
|
(e.g., two threads tried to join with each other);
|
|
or
|
|
|
|
<I>thread</I>
|
|
|
|
specifies the calling thread.
|
|
<DT id="2"><B>EINVAL</B>
|
|
|
|
<DD>
|
|
<I>thread</I>
|
|
|
|
is not a joinable thread.
|
|
<DT id="3"><B>EINVAL</B>
|
|
|
|
<DD>
|
|
Another thread is already waiting to join with this thread.
|
|
|
|
<DT id="4"><B>ESRCH</B>
|
|
|
|
<DD>
|
|
No thread with the ID
|
|
<I>thread</I>
|
|
|
|
could be found.
|
|
</DL>
|
|
<A NAME="lbAG"> </A>
|
|
<H2>ATTRIBUTES</H2>
|
|
|
|
For an explanation of the terms used in this section, see
|
|
<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
|
|
|
|
<TABLE BORDER>
|
|
<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
|
|
<TR VALIGN=top><TD>
|
|
<B>pthread_join</B>()
|
|
|
|
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
|
|
</TABLE>
|
|
|
|
<P>
|
|
<A NAME="lbAH"> </A>
|
|
<H2>CONFORMING TO</H2>
|
|
|
|
POSIX.1-2001, POSIX.1-2008.
|
|
<A NAME="lbAI"> </A>
|
|
<H2>NOTES</H2>
|
|
|
|
After a successful call to
|
|
<B>pthread_join</B>(),
|
|
|
|
the caller is guaranteed that the target thread has terminated.
|
|
The caller may then choose to do any clean-up that is required
|
|
after termination of the thread (e.g., freeing memory or other
|
|
resources that were allocated to the target thread).
|
|
<P>
|
|
|
|
Joining with a thread that has previously been joined results in
|
|
undefined behavior.
|
|
<P>
|
|
|
|
Failure to join with a thread that is joinable
|
|
(i.e., one that is not detached),
|
|
produces a "zombie thread".
|
|
Avoid doing this,
|
|
since each zombie thread consumes some system resources,
|
|
and when enough zombie threads have accumulated,
|
|
it will no longer be possible to create new threads (or processes).
|
|
<P>
|
|
|
|
There is no pthreads analog of
|
|
<I>waitpid(-1, &status, 0)</I>,
|
|
|
|
that is, "join with any terminated thread".
|
|
If you believe you need this functionality,
|
|
you probably need to rethink your application design.
|
|
<P>
|
|
|
|
All of the threads in a process are peers:
|
|
any thread can join with any other thread in the process.
|
|
<A NAME="lbAJ"> </A>
|
|
<H2>EXAMPLE</H2>
|
|
|
|
See
|
|
<B><A HREF="/cgi-bin/man/man2html?3+pthread_create">pthread_create</A></B>(3).
|
|
|
|
<A NAME="lbAK"> </A>
|
|
<H2>SEE ALSO</H2>
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?3+pthread_cancel">pthread_cancel</A></B>(3),
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?3+pthread_create">pthread_create</A></B>(3),
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?3+pthread_detach">pthread_detach</A></B>(3),
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?3+pthread_exit">pthread_exit</A></B>(3),
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?3+pthread_tryjoin_np">pthread_tryjoin_np</A></B>(3),
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?7+pthreads">pthreads</A></B>(7)
|
|
|
|
<A NAME="lbAL"> </A>
|
|
<H2>COLOPHON</H2>
|
|
|
|
This page is part of release 5.05 of the Linux
|
|
<I>man-pages</I>
|
|
|
|
project.
|
|
A description of the project,
|
|
information about reporting bugs,
|
|
and the latest version of this page,
|
|
can be found at
|
|
<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
|
|
<P>
|
|
|
|
<HR>
|
|
<A NAME="index"> </A><H2>Index</H2>
|
|
<DL>
|
|
<DT id="5"><A HREF="#lbAB">NAME</A><DD>
|
|
<DT id="6"><A HREF="#lbAC">SYNOPSIS</A><DD>
|
|
<DT id="7"><A HREF="#lbAD">DESCRIPTION</A><DD>
|
|
<DT id="8"><A HREF="#lbAE">RETURN VALUE</A><DD>
|
|
<DT id="9"><A HREF="#lbAF">ERRORS</A><DD>
|
|
<DT id="10"><A HREF="#lbAG">ATTRIBUTES</A><DD>
|
|
<DT id="11"><A HREF="#lbAH">CONFORMING TO</A><DD>
|
|
<DT id="12"><A HREF="#lbAI">NOTES</A><DD>
|
|
<DT id="13"><A HREF="#lbAJ">EXAMPLE</A><DD>
|
|
<DT id="14"><A HREF="#lbAK">SEE ALSO</A><DD>
|
|
<DT id="15"><A HREF="#lbAL">COLOPHON</A><DD>
|
|
</DL>
|
|
<HR>
|
|
This document was created by
|
|
<A HREF="/cgi-bin/man/man2html">man2html</A>,
|
|
using the manual pages.<BR>
|
|
Time: 00:05:53 GMT, March 31, 2021
|
|
</BODY>
|
|
</HTML>
|