pthread_timedjoin_np(3)

1PTHREAD_TRYJOIN_NP(3)      Linux Programmer's Manual     PTHREAD_TRYJOIN_NP(3)
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NAME

6       pthread_tryjoin_np,  pthread_timedjoin_np  -  try to join with a termi‐
7       nated thread
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SYNOPSIS

10       #define _GNU_SOURCE             /* See feature_test_macros(7) */
11       #include <pthread.h>
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13       int pthread_tryjoin_np(pthread_t thread, void **retval);
14       int pthread_timedjoin_np(pthread_t thread, void **retval,
15                                const struct timespec *abstime);
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17       Compile and link with -pthread.
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DESCRIPTION

20       These functions operate in the same way as pthread_join(3), except  for
21       the differences described on this page.
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23       The  pthread_tryjoin_np() function performs a nonblocking join with the
24       thread thread, returning the exit status of the thread in *retval.   If
25       thread  has not yet terminated, then instead of blocking, as is done by
26       pthread_join(3), the call returns an error.
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28       The pthread_timedjoin_np() function performs a  join-with-timeout.   If
29       thread  has  not  yet  terminated, then the call blocks until a maximum
30       time, specified in abstime, measured against the CLOCK_REALTIME  clock.
31       If  the  timeout  expires before thread terminates, the call returns an
32       error.  The abstime argument is a  structure  of  the  following  form,
33       specifying an absolute time measured since the Epoch (see time(2)):
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35           struct timespec {
36               time_t tv_sec;     /* seconds */
37               long   tv_nsec;    /* nanoseconds */
38           };
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RETURN VALUE

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

45       These functions can fail  with  the  same  errors  as  pthread_join(3).
46       pthread_tryjoin_np() can in addition fail with the following error:
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48       EBUSY  thread had not yet terminated at the time of the call.
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50       pthread_timedjoin_np() can in addition fail with the following errors:
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52       ETIMEDOUT
53              The call timed out before thread terminated.
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55       EINVAL abstime  value  is  invalid (tv_sec is less than 0 or tv_nsec is
56              greater than 1e9).
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58       pthread_timedjoin_np() never returns the error EINTR.
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VERSIONS

61       These functions first appeared in glibc in version 2.3.3.
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ATTRIBUTES

64       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
65       tributes(7).
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67       ┌────────────────────────────────────────────┬───────────────┬─────────┐
68       │Interface                                   │ Attribute     │ Value   │
69       ├────────────────────────────────────────────┼───────────────┼─────────┤
70       │pthread_tryjoin_np(),                       │ Thread safety │ MT-Safe │
71       │pthread_timedjoin_np()                      │               │         │
72       └────────────────────────────────────────────┴───────────────┴─────────┘
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CONFORMING TO

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

79       The following code waits to join for up to 5 seconds:
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81           struct timespec ts;
82           int s;
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84           ...
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86           if (clock_gettime(CLOCK_REALTIME, &ts) == -1) {
87               /* Handle error */
88           }
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90           ts.tv_sec += 5;
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92           s = pthread_timedjoin_np(thread, NULL, &ts);
93           if (s != 0) {
94               /* Handle error */
95           }
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BUGS

98       The  pthread_timedjoin_np() function measures time by internally calcu‐
99       lating a relative sleep interval that  is  then  measured  against  the
100       CLOCK_MONOTONIC  clock  instead  of  the  CLOCK_REALTIME clock.  Conse‐
101       quently, the timeout is unaffected  by  discontinuous  changes  to  the
102       CLOCK_REALTIME clock.
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COLOPHON

108       This  page  is  part of release 5.12 of the Linux man-pages project.  A
109       description of the project, information about reporting bugs,  and  the
110       latest     version     of     this    page,    can    be    found    at
111       https://www.kernel.org/doc/man-pages/.
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115Linux                             2021-03-22             PTHREAD_TRYJOIN_NP(3)