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pthread_join(3c) [opensolaris man page]

pthread_join(3C)					   Standard C Library Functions 					  pthread_join(3C)

NAME
pthread_join - wait for thread termination SYNOPSIS
cc -mt [ flag... ] file... -lpthread [ library... ] #include <pthread.h> int pthread_join(pthread_t thread, void **status); DESCRIPTION
The pthread_join() function suspends processing of the calling thread until the target thread completes. thread must be a member of the current process and it cannot be a detached thread. See pthread_create(3C). If two or more threads wait for the same thread to complete, all will suspend processing until the thread has terminated, and then one thread will return successfully and the others will return with an error of ESRCH. The pthread_join() function will not block processing of the calling thread if the target thread has already terminated. If a pthread_join() call returns successfully with a non-null status argument, the value passed to pthread_exit(3C) by the terminating thread will be placed in the location referenced by status. If the pthread_join() calling thread is cancelled, then the target thread will remain joinable by pthread_join(). However, the calling thread may set up a cancellation cleanup handler on thread prior to the join call, which may detach the target thread by calling pthread_detach(3C). See pthread_detach(3C) and pthread_cancel(3C). RETURN VALUES
If successful, pthread_join() returns 0. Otherwise, an error number is returned to indicate the error. ERRORS
EDEADLK A joining deadlock would occur, such as when a thread attempts to wait for itself. EINVAL The thread corresponding to the given thread ID is a detached thread. ESRCH No thread could be found corresponding to the given thread ID. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
pthread_cancel(3C), pthread_create(3C), pthread_detach(3C), pthread_exit(3C), wait(3C), attributes(5), standards(5) NOTES
The pthread_join(3C) function must specify the thread ID for whose termination it will wait. Calling pthread_join() also "detaches" the thread; that is, pthread_join() includes the effect of the pthread_detach() function. If a thread were to be cancelled when blocked in pthread_join(), an explicit detach would have to be performed in the cancellation cleanup han- dler. The pthread_detach() function exists primarily for this purpose. SunOS 5.11 23 Mar 2005 pthread_join(3C)

Check Out this Related Man Page

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 3.44 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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