pthread_tryjoin_np (3)
Leading comments
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NAME
pthread_tryjoin_np, pthread_timedjoin_np - try to join with a terminated threadSYNOPSIS
#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. 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(), pthread_timedjoin_np() | Thread safety | MT-Safe |
CONFORMING TO
These functions are nonstandard GNU extensions; hence the suffix "_np" (nonportable) in the names.EXAMPLE
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 */ }