1.\" Copyright (c) 1996-1998 John Birrell <jb@cimlogic.com.au>. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by John Birrell. 15.\" 4. Neither the name of the author nor the names of any co-contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" $FreeBSD$ 32.\" 33.Dd October 12, 2021 34.Dt PTHREAD_JOIN 3 35.Os 36.Sh NAME 37.Nm pthread_join , 38.Nm pthread_peekjoin_np , 39.Nm pthread_timedjoin_np 40.Nd inspect thread termination state 41.Sh LIBRARY 42.Lb libpthread 43.Sh SYNOPSIS 44.In pthread.h 45.Ft int 46.Fn pthread_join "pthread_t thread" "void **value_ptr" 47.In pthread_np.h 48.Ft int 49.Fo pthread_peekjoin_np 50.Fa "pthread_t thread" 51.Fa "void **value_ptr" 52.Fc 53.Ft int 54.Fo pthread_timedjoin_np 55.Fa "pthread_t thread" 56.Fa "void **value_ptr" 57.Fa "const struct timespec *abstime" 58.Fc 59.Sh DESCRIPTION 60The 61.Fn pthread_join 62function suspends execution of the calling thread until the target 63.Fa thread 64terminates unless the target 65.Fa thread 66has already terminated. 67.Pp 68On return from a successful 69.Fn pthread_join 70call with a non-NULL 71.Fa value_ptr 72argument, the value passed to 73.Fn pthread_exit 74by the terminating thread is stored in the location referenced by 75.Fa value_ptr . 76When a 77.Fn pthread_join 78returns successfully, the target thread has been terminated. 79The results 80of multiple simultaneous calls to 81.Fn pthread_join 82specifying the same target thread are undefined. 83If the thread calling 84.Fn pthread_join 85is cancelled, then the target thread is not detached. 86.Pp 87The 88.Fn pthread_timedjoin_np 89function is equivalent to the 90.Fn pthread_join 91function except it will return 92.Er ETIMEDOUT 93if target thread does not exit before specified absolute time passes. 94.Pp 95The 96.Fn pthread_peekjoin_np 97only peeks into the exit status of the specified thread. 98If the thread has not exited, the 99.Er EBUSY 100error is returned. 101Otherwise, zero is returned and the thread exit value is optionally stored 102into the location of 103.Fa *value_ptr . 104The target thread is left unjoined and can be used as an argument for 105the 106.Fn pthread_join 107family of functions again. 108.Pp 109A thread that has exited but remains unjoined counts against 110[_POSIX_THREAD_THREADS_MAX]. 111.Sh RETURN VALUES 112If successful, the described functions return zero. 113Otherwise an error number is returned to indicate the error or 114special condition. 115.Sh ERRORS 116The 117.Fn pthread_join , 118.Fn pthread_peekjoin_np , 119and 120.Fn pthread_timedjoin_np 121functions will fail if: 122.Bl -tag -width Er 123.It Bq Er EINVAL 124The implementation has detected that the value specified by 125.Fa thread 126does not refer to a joinable thread. 127.It Bq Er ESRCH 128No thread could be found corresponding to that specified by the given 129thread ID, 130.Fa thread . 131.It Bq Er EDEADLK 132A deadlock was detected or the value of 133.Fa thread 134specifies the calling thread. 135.It Bq Er EOPNOTSUPP 136The implementation detected that another caller is already waiting on 137.Fa thread . 138.El 139.Pp 140Additionally, the 141.Fn pthread_timedjoin_np 142function will fail if: 143.Bl -tag -width Er 144.It Bq Er ETIMEDOUT 145The specified absolute time passed while 146.Fn pthread_timedjoin_np 147waited for thread exit. 148.El 149.Pp 150The 151.Fn pthread_peekjoin_np 152function will also fail if: 153.Bl -tag -width Er 154.It Bq Er EBUSY 155The specified thread has not yet exited. 156.El 157.Sh SEE ALSO 158.Xr wait 2 , 159.Xr pthread 3 , 160.Xr pthread_create 3 , 161.Xr pthread_np 3 162.Sh STANDARDS 163The 164.Fn pthread_join 165function conforms to 166.St -p1003.1-96 . 167The 168.Fn pthread_timedjoin_np 169function is a 170.Fx 171extension which first appeared in 172.Fx 6.1 . 173Another extension, the 174.Fn pthread_peekjoin_np 175function, first appearead in 176.Fx 13.0 . 177