1PTHREAD_TRYJOIN_NP(3) Linux Programmer's Manual PTHREAD_TRYJOIN_NP(3)
2
6 pthread_tryjoin_np, pthread_timedjoin_np - try to join with a termi‐
7 nated thread
8
10 #define _GNU_SOURCE /* See feature_test_macros(7) */
11 #include <pthread.h>
12 int pthread_tryjoin_np(pthread_t thread, void **retval);
14 int pthread_timedjoin_np(pthread_t thread, void **retval,
15 const struct timespec *abstime);
16 Compile and link with -pthread.
18
20 These functions operate in the same way as pthread_join(3), except for
21 the differences described on this page.
22 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.
27 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)):
34 struct timespec {
36 time_t tv_sec; /* seconds */
37 long tv_nsec; /* nanoseconds */
38 };
39
41 On success, these functions return 0; on error, they return an error
42 number.
43
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:
47 EBUSY thread had not yet terminated at the time of the call.
49 pthread_timedjoin_np() can in addition fail with the following errors:
51 EINVAL abstime value is invalid (tv_sec is less than 0 or tv_nsec is
53 greater than 1e9).
54 ETIMEDOUT
56 The call timed out before thread terminated.
57 pthread_timedjoin_np() never returns the error EINTR.
59
61 These functions first appeared in glibc in version 2.3.3.
62
64 For an explanation of the terms used in this section, see at‐
65 tributes(7).
66 ┌────────────────────────────────────────────┬───────────────┬─────────┐
68 │Interface │ Attribute │ Value │
69 ├────────────────────────────────────────────┼───────────────┼─────────┤
70 │pthread_tryjoin_np(), │ Thread safety │ MT-Safe │
71 │pthread_timedjoin_np() │ │ │
72 └────────────────────────────────────────────┴───────────────┴─────────┘
73
75 These functions are nonstandard GNU extensions; hence the suffix "_np"
76 (nonportable) in the names.
77
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.
84
86 The following code waits to join for up to 5 seconds:
87 struct timespec ts;
89 int s;
90 ...
92 if (clock_gettime(CLOCK_REALTIME, &ts) == -1) {
94 /* Handle error */
95 }
96 ts.tv_sec += 5;
98 s = pthread_timedjoin_np(thread, NULL, &ts);
100 if (s != 0) {
101 /* Handle error */
102 }
103
105 clock_gettime(2), pthread_exit(3), pthread_join(3), pthreads(7)
106
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/.
112Linux 2021-08-27 PTHREAD_TRYJOIN_NP(3)