HP-UX Reference (11i v3 07/02) - 3 Library Functions N-Z (vol 7)

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pthread_join(3T) pthread_join(3T)

(Pthread Library)

NAME

pthread_join() - wait for the termination of a speciﬁed thread

SYNOPSIS

#include <pthread.h>

int pthread_join(

pthread_t thread,

void **value_ptr

);

PARAMETERS

thread Thread whose termination is awaited by the caller.

value_ptr Pointer to the location where the exit status of thread is returned.

DESCRIPTION

The

pthread_join()

function waits for the termination of the target thread. If the target thread has

already terminated, this function returns immediately. Only threads created with a detachstate attribute

value of

PTHREAD_CREATE_JOINABLE

may be speciﬁed in the target thread parameter. On successful

return from

pthread_join()

, the value_ptr argument, if it is not a null pointer, will contain the value

passed to

pthread_exit() by the terminating thread.

When a

pthread_join() call returns successfully, the caller is guaranteed the target thread has ter-

minated. If more than one thread calls

pthread_join()

for the same target thread, one thread is

guaranteed to return successfully. Undeﬁned behavior results for other callers specifying the same thread.

If the thread calling

pthread_join()

is canceled, the target thread shall not be joined. The exit status

of the target thread will remain available for another thread to call

pthread_join()

If the target thread was canceled, its exit status is

PTHREAD_CANCELED

It is unspeciﬁed whether a thread that has exited, but remains unjoined, counts against the

{_POSIX_THREAD_THREADS_MAX}

limit.

RETURN VALUE

Upon successful completion,

pthread_join()

returns zero. Otherwise, an error number is returned to

indicate the error (the

errno variable is not set).

ERRORS

If any of the following occur, the pthread_join()

function returns the corresponding error number:

[EINVAL] The value speciﬁed by thread does not refer to a joinable thread.

[ESRCH] No thread could be found corresponding to thread.

For each of the following conditions, if the condition is detected, the

pthread_join()

function returns

the corresponding error number:

[EDEADLK] This operation would result in process deadlock or thread speciﬁes the calling thread.

AUTHOR

pthread_join() was derived from the IEEE POSIX P1003.1c standard.