PTHREAD_TRYJOIN_NP(3) - man page online | library functions

Try to join with a terminated thread.

PTHREAD_TRYJOIN_NP(3)               Linux Programmer's Manual               PTHREAD_TRYJOIN_NP(3)


pthread_tryjoin_np, pthread_timedjoin_np - try to join with a terminated thread


#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); 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 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. If the time‐ out 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 errors: ETIMEDOUT The call timed out before thread terminated. EINVAL abstime value is invalid (tv_sec is less than 0 or tv_nsec is greater than 1e9). pthread_timedjoin_np() never returns the error EINTR.


These functions first appeared in glibc in version 2.3.3.


For an explanation of the terms used in this section, see attributes(7). ┌───────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├───────────────────────┼───────────────┼─────────┤ │pthread_tryjoin_np(), │ Thread safety │ MT-Safe │ │pthread_timedjoin_np() │ │ │ └───────────────────────┴───────────────┴─────────┘


These functions are nonstandard GNU extensions; hence the suffix "_np" (nonportable) 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_exit(3), pthread_join(3), pthreads(7)


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Linux 2015-07-23 PTHREAD_TRYJOIN_NP(3)
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pthread_tryjoin_np(3) referred by pthread_join(3)
refer to attributes(7) | clock_getres(2) | feature_test_macros(7) | pthread_exit(3) | pthread_join(3) | pthreads(7) | time(2)