1PTHREAD_TRYJOIN_NP(3) Linux Programmer's Manual PTHREAD_TRYJOIN_NP(3)
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6 pthread_tryjoin_np, pthread_timedjoin_np - try to join with a termi‐
7 nated thread
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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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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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41 On success, these functions return 0; on error, they return an error
42 number.
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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 EINVAL abstime value is invalid (tv_sec is less than 0 or tv_nsec is
53 greater than 1e9).
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55 ETIMEDOUT
56 The call timed out before thread terminated.
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58 pthread_timedjoin_np() never returns the error EINTR.
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61 These functions first appeared in glibc in version 2.3.3.
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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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75 These functions are nonstandard GNU extensions; hence the suffix "_np"
76 (nonportable) in the names.
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79 The pthread_timedjoin_np() function measures time by internally calcu‐
80 lating a relative sleep interval that is then measured against the
81 CLOCK_MONOTONIC clock instead of the CLOCK_REALTIME clock. Consequent‐
82 ly, the timeout is unaffected by discontinuous changes to the CLOCK_RE‐
83 ALTIME clock.
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86 The following code waits to join for up to 5 seconds:
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88 struct timespec ts;
89 int s;
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91 ...
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93 if (clock_gettime(CLOCK_REALTIME, &ts) == -1) {
94 /* Handle error */
95 }
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97 ts.tv_sec += 5;
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99 s = pthread_timedjoin_np(thread, NULL, &ts);
100 if (s != 0) {
101 /* Handle error */
102 }
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105 clock_gettime(2), pthread_exit(3), pthread_join(3), pthreads(7)
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108 This page is part of release 5.13 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 2021-08-27 PTHREAD_TRYJOIN_NP(3)