NAME

       pthread_tryjoin_np, pthread_timedjoin_np - try to join with a terminated thread

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);

       Compile and link with -pthread.

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 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

       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:

       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

       These functions first appeared in glibc in version 2.3.3.

ATTRIBUTES

       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

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

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 */
           }

BUGS

       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

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

COLOPHON

       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/.