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.TH PTHREAD_TRYJOIN_NP 3 2010-09-10 "Linux" "Linux Programmer's Manual"
.SH NAME
pthread_tryjoin_np, pthread_timedjoin_np \- try to join with a
terminated thread
.SH SYNOPSIS
.nf
.BR "#define _GNU_SOURCE" "             /* See feature_test_macros(7) */"
.B #include <pthread.h>

.BI "int pthread_tryjoin_np(pthread_t " thread ", void **" retval );

.BI "int pthread_timedjoin_np(pthread_t " thread ", void **" retval ,
.BI "                         const struct timespec *" abstime );
.fi
.sp
Compile and link with \fI\-pthread\fP.
.SH DESCRIPTION
These functions operate in the same way as
.BR pthread_join (3),
except for the differences described on this page.

The
.BR pthread_tryjoin_np ()
function performs a nonblocking join with the thread
.IR thread ,
returning the exit status of the thread in
.IR *retval .
If
.I thread
has not yet terminated, then instead of blocking, as is done by
.BR pthread_join (3),
the call returns an error.

The
.BR pthread_timedjoin_np ()
function performs a join-with-timeout.
If
.I thread
has not yet terminated,
then the call blocks until a maximum time, specified in
.IR abstime .
If the timeout expires before
.I thread
terminates,
the call returns an error.
The
.I abstime
argument is a structure of the following form,
specifying an absolute time measured since the Epoch (see
.BR time (2)):

.in +4n
.nf
struct timespec {
    time_t tv_sec;     /* seconds */
    long   tv_nsec;    /* nanoseconds */
};
.fi
.in
.SH RETURN VALUE
On success,
these functions return 0;
on error, they return an error number.
.SH ERRORS
These functions can fail with the same errors as
.BR pthread_join (3).
.BR pthread_tryjoin_np ()
can in addition fail with the following error:
.TP
.B EBUSY
.I thread
had not yet terminated at the time of the call.
.PP
.BR pthread_timedjoin_np ()
can in addition fail with the following error:
.TP
.BR ETIMEDOUT
The call timed out before
.I thread
terminated.
.PP
.BR pthread_timedjoin_np ()
never returns the error
.BR EINTR .
.SH VERSIONS
These functions first appeared in glibc in version 2.3.3.
.SH CONFORMING TO
These functions are nonstandard GNU extensions;
hence the suffix "_np" (nonportable) in the names.
.SH EXAMPLE
The following code waits to join for up to 5 seconds:

.nf
    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 */
    }
.fi
.SH SEE ALSO
.BR clock_gettime (2),
.BR pthread_exit (3),
.BR pthread_join (3),
.BR pthreads (7)