pthread_tryjoin_np, pthread_timedjoin_np - try to join with a terminated thread


#define _GNU_SOURCE #include <pthread.h>

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

int pthread_timedjoin_np(pthread_t thread, void **retval, const struct timespec *abstime);

Compile and link with -pthread.


These functions operate in the same way as pthread_join(3), except for the differences described on this page.

The pthread_tryjoin_np() function performs a non-blocking join with the thread thread, returning the exit status of the thread in *retval. If thread has not yet terminated, then instead of blocking, as is done by pthread_join(3), the call returns an error.

The pthread_timedjoin_np() function performs a join-with-timeout. If thread has not yet terminated, then the call blocks until a maximum time, specified in abstime. If the timeout expires before thread terminates, the call returns an error. The abstime argument is a structure of the following form, specifying an absolute time measured since the Epoch (see time(2)):

struct timespec { time_t tv_sec; /* seconds */ long tv_nsec; /* nanoseconds */ };


On success, these functions return 0; on error, they return an error number.


These functions can fail with the same errors as pthread_join(3). pthread_tryjoin_np() can in addition fail with the following error:
EBUSY thread had not yet terminated at the time of the call.
pthread_timedjoin_np() can in addition fail with the following error:
 The call timed out before thread terminated.
pthread_timedjoin_np() never returns the error EINTR.


These functions first appeared in glibc in version 2.3.3.


These functions are non-standard GNU extensions; hence the suffix "_np" (non-portable) in the names.


The following code waits to join for up to 5 seconds:

struct timespec ts; int s;


if (clock_gettime(CLOCK_REALTIME, &ts) == -1) {         /* Handle error */ }

ts.tv_sec += 5;

s = pthread_timedjoin_np(thread, NULL, &ts); if (s != 0) { /* Handle error */ }


clock_gettime(2), pthread_join(3), pthread_exit(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

openSUSE Logo