pthread_tryjoin_np(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | ATTRIBUTES | CONFORMING TO | EXAMPLES | BUGS | SEE ALSO | COLOPHON

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

NAME         top

       pthread_tryjoin_np, pthread_timedjoin_np - try to join with a
       terminated thread

SYNOPSIS         top

       #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.

DESCRIPTION         top

       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
       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 */
           };

RETURN VALUE         top

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

ERRORS         top

       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.

VERSIONS         top

       These functions first appeared in glibc in version 2.3.3.

ATTRIBUTES         top

       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() │               │         │
       └───────────────────────┴───────────────┴─────────┘

CONFORMING TO         top

       These functions are nonstandard GNU extensions; hence the suffix
       "_np" (nonportable) in the names.

EXAMPLES         top

       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 */
           }

BUGS         top

       The pthread_timedjoin_np() function measures time by internally
       calculating a relative sleep interval that is then measured
       against the CLOCK_MONOTONIC clock instead of the CLOCK_REALTIME
       clock.  Consequently, the timeout is unaffected by discontinuous
       changes to the CLOCK_REALTIME clock.

SEE ALSO         top

       clock_gettime(2), pthread_exit(3), pthread_join(3), pthreads(7)

COLOPHON         top

       This page is part of release 5.10 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

Linux                          2020-12-21          PTHREAD_TRYJOIN_NP(3)

Pages that refer to this page: pthread_join(3)