pthread_tryjoin_np(3) Library Functions Manual pthread_tryjoin_np(3) NAME pthread_tryjoin_np, pthread_timedjoin_np - try to join with a termi- nated thread LIBRARY POSIX threads library (libpthread, -lpthread) SYNOPSIS #define _GNU_SOURCE /* See feature_test_macros(7) */ #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); DESCRIPTION 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 nonblocking 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, measured against the CLOCK_REALTIME clock. If the timeout expires before thread terminates, the call returns an error. The abstime argument is a timespec(3) structure, specifying an absolute time measured since the Epoch (see time(2)). RETURN VALUE On success, these functions return 0; on error, they return an error number. ERRORS 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 errors: EINVAL abstime value is invalid (tv_sec is less than 0 or tv_nsec is greater than 1e9). ETIMEDOUT The call timed out before thread terminated. pthread_timedjoin_np() never returns the error EINTR. VERSIONS These functions were added in glibc 2.3.3. ATTRIBUTES For an explanation of the terms used in this section, see at- tributes(7). ┌────────────────────────────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├────────────────────────────────────────────┼───────────────┼─────────┤ │pthread_tryjoin_np(), │ Thread safety │ MT-Safe │ │pthread_timedjoin_np() │ │ │ └────────────────────────────────────────────┴───────────────┴─────────┘ STANDARDS These functions are nonstandard GNU extensions; hence the suffix "_np" (nonportable) in the names. BUGS The pthread_timedjoin_np() function measures time by internally calcu- lating a relative sleep interval that is then measured against the CLOCK_MONOTONIC clock instead of the CLOCK_REALTIME clock. Consequent- ly, the timeout is unaffected by discontinuous changes to the CLOCK_RE- ALTIME clock. EXAMPLES 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 */ } SEE ALSO clock_gettime(2), pthread_exit(3), pthread_join(3), timespec(3), pthreads(7) Linux man-pages 6.03 2022-12-15 pthread_tryjoin_np(3)
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