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   pthread_join    ( 3 )

присоединиться к завершенному потоку (join with a terminated thread)

Имя (Name)

pthread_join - join with a terminated thread

Синопсис (Synopsis)

#include <pthread.h>

int pthread_join(pthread_t thread, void **retval);

Compile and link with -pthread.


Описание (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 the location pointed to by 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).


Возвращаемое значение (Return value)

On success, pthread_join() returns 0; on error, it returns an
       error number.

Ошибки (Error)

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.


Атрибуты (Attributes)

For an explanation of the terms used in this section, see
       attributes(7).

┌──────────────────────────────────────┬───────────────┬─────────┐ │Interface Attribute Value │ ├──────────────────────────────────────┼───────────────┼─────────┤ │pthread_join() │ Thread safety │ MT-Safe │ └──────────────────────────────────────┴───────────────┴─────────┘


Стандарты (Conforming to)

POSIX.1-2001, POSIX.1-2008.

Примечание (Note)

After a successful call to pthread_join(), 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).

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.


Примеры (Examples)

See pthread_create(3).

Смотри также (See also)

pthread_cancel(3), pthread_create(3), pthread_detach(3),
       pthread_exit(3), pthread_tryjoin_np(3), pthreads(7)