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pthread_join(3) [freebsd man page]

PTHREAD_JOIN(3) 					   BSD Library Functions Manual 					   PTHREAD_JOIN(3)

NAME
pthread_join, pthread_timedjoin_np -- wait for thread termination LIBRARY
POSIX Threads Library (libpthread, -lpthread) SYNOPSIS
#include <pthread.h> int pthread_join(pthread_t thread, void **value_ptr); int pthread_timedjoin_np(pthread_t thread, void **value_ptr, const struct timespec *abstime); DESCRIPTION
The pthread_join() function suspends execution of the calling thread until the target thread terminates unless the target thread has already terminated. On return from a successful pthread_join() call with a non-NULL value_ptr argument, the value passed to pthread_exit() by the terminating thread is stored in the location referenced by value_ptr. When a pthread_join() returns successfully, the target thread has been terminated. The results of multiple simultaneous calls to pthread_join() specifying the same target thread are undefined. If the thread calling pthread_join() is cancelled, then the target thread is not detached. The pthread_timedjoin_np() function is equivalent to the pthread_join() function except it will return ETIMEDOUT if target thread does not exit before specified absolute time passes. A thread that has exited but remains unjoined counts against [_POSIX_THREAD_THREADS_MAX]. RETURN VALUES
If successful, the pthread_join() and pthread_timedjoin_np() functions will return zero. Otherwise an error number will be returned to indi- cate the error. ERRORS
The pthread_join() and pthread_timedjoin_np() functions will 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, thread. [EDEADLK] A deadlock was detected or the value of thread specifies the calling thread. [EOPNOTSUPP] The implementation detected that another caller is already waiting on thread. Additionally, the pthread_timedjoin_np() function will fail if: [ETIMEDOUT] The specified absolute time passed while pthread_timedjoin_np() waited for thread exit. SEE ALSO
wait(2), pthread_create(3) STANDARDS
The pthread_join() function conforms to ISO/IEC 9945-1:1996 (``POSIX.1''). The pthread_timedjoin_np() is a FreeBSD extension which first appeared in FreeBSD 6.1. BSD
January 23, 2010 BSD

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

NAME
pthread_join - join with a terminated thread SYNOPSIS
#include <pthread.h> int pthread_join(pthread_t thread, void **retval); Compile and link with -pthread. DESCRIPTION
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). RETURN VALUE
On success, pthread_join() returns 0; on error, it returns an error number. ERRORS
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. CONFORMING TO
POSIX.1-2001. NOTES
After a successful call to pthread_join(), 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 function- ality, 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. EXAMPLE
See pthread_create(3). SEE ALSO
pthread_cancel(3), pthread_create(3), pthread_detach(3), pthread_exit(3), pthread_tryjoin_np(3), pthreads(7) COLOPHON
This page is part of release 3.53 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)
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