NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | NOTES | EXAMPLE | SEE ALSO | COLOPHON
PTHREAD_JOIN(3) Linux Programmer's Manual PTHREAD_JOIN(3)
pthread_join - join with a terminated thread
#include <pthread.h>
int pthread_join(pthread_t thread, void **retval);
Compile and link with -pthread.
The pthread_join() function waits for the thread specified by thread to
terminate. If that thread has already terminated, then pthread_join() returns
immediately. The thread specified by thread must be joinable.
If retval is not NULL, then pthread_join() copies the exit status of the
target thread (i.e., the value that the target thread supplied to
pthread_exit(3)) into the location pointed to by *retval. If the target
thread was canceled, then PTHREAD_CANCELED is placed in *retval.
If multiple threads simultaneously try to join with the same thread, the
results are undefined. If the thread calling pthread_join() is canceled, then
the target thread will remain joinable (i.e., it will not be detached).
On success, pthread_join() returns 0; on error, it returns an error number.
EDEADLK
A deadlock was detected (e.g., two threads tried to join with each
other); or thread specifies the calling thread.
EINVAL thread is not a joinable thread.
EINVAL Another thread is already waiting to join with this thread.
ESRCH No thread with the ID thread could be found.
POSIX.1-2001.
After a successful call to pthread_create(), the caller is guaranteed that the
target thread has terminated.
Joining with a thread that has previously been joined results in undefined
behavior.
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).
There is no pthreads analog of waitpid(-1, &status, 0), that is, "join with
any terminated thread". If you believe you need this functionality, you
probably need to rethink your application design.
All of the threads in a process are peers: any thread can join with any other
thread in the process.
See pthread_create(3).
pthread_cancel(3), pthread_create(3), pthread_detach(3), pthread_exit(3),
pthread_tryjoin_np(3), pthreads(7)
This page is part of release 3.23 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
Linux 2008-11-27 PTHREAD_JOIN(3)