1 .\" Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk
2 .\" <mtk.manpages@gmail.com>
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26 .TH PTHREAD_JOIN 3 2008-11-27 "Linux" "Linux Programmer's Manual"
28 pthread_join \- join with a terminated thread
31 .B #include <pthread.h>
33 .BI "int pthread_join(pthread_t " thread ", void **" retval );
36 Compile and link with \fI\-pthread\fP.
40 function waits for the thread specified by
43 If that thread has already terminated, then
46 The thread specified by
54 copies the exit status of the target thread
55 (i.e., the value that the target thread supplied to
57 into the location pointed to by
59 If the target thread was canceled, then
64 If multiple threads simultaneously try to join with the same thread,
65 the results are undefined.
68 is canceled, then the target thread will remain joinable
69 (i.e., it will not be detached).
74 on error, it returns an error number.
78 A deadlock was detected
79 .\" The following verified by testing on glibc 2.8/NPTL:
80 (e.g., two threads tried to join with each other);
82 .\" The following verified by testing on glibc 2.8/NPTL:
84 specifies the calling thread.
88 is not a joinable thread.
91 Another thread is already waiting to join with this thread.
92 .\" POSIX.1-2001 does not specify this error case.
101 After a successful call to
103 the caller is guaranteed that the target thread has terminated.
105 Joining with a thread that has previously been joined results in
108 Failure to join with a thread that is joinable
109 (i.e., one that is not detached),
110 produces a "zombie thread".
112 since each zombie thread consumes some system resources,
113 and when enough zombie threads have accumulated,
114 it will no longer be possible to create new threads (or processes).
116 There is no pthreads analog of
117 .IR "waitpid(-1,\ &status,\ 0)" ,
118 that is, "join with any terminated thread".
119 If you believe you need this functionality,
120 you probably need to rethink your application design.
122 All of the threads in a process are peers:
123 any thread can join with any other thread in the process.
126 .BR pthread_create (3).
128 .BR pthread_cancel (3),
129 .BR pthread_create (3),
130 .BR pthread_detach (3),
131 .BR pthread_exit (3),
132 .BR pthread_tryjoin_np (3),
135 This page is part of release 3.79 of the Linux
138 A description of the project,
139 information about reporting bugs,
140 and the latest version of this page,
142 \%http://www.kernel.org/doc/man\-pages/.