'\" te
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.TH pthread_join 3C "11 Jan 2012" "SunOS 5.11" "Standard C Library Functions"
.SH NAME
pthread_join \- wait for thread termination
.SH SYNOPSIS
.LP
.nf
cc -mt [ \fIflag\fR... ] \fIfile\fR... [ \fIlibrary\fR... ]
#include <pthread.h>

\fBint\fR \fBpthread_join\fR(\fBpthread_t\fR \fIthread\fR, \fBvoid **\fR\fIstatus\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBpthread_join()\fR function suspends processing of the calling thread until the target \fIthread\fR completes. \fIthread\fR must be a member of the current process and it cannot be a detached thread. See \fBpthread_create\fR(3C). 
.sp
.LP
If two or more threads wait for the same thread to complete, all will suspend processing until the thread has terminated, and then one thread will return successfully and the others will return with an error of \fBESRCH\fR. The \fBpthread_join()\fR function will not block processing of the calling thread if the target \fIthread\fR has already terminated.
.sp
.LP
If a \fBpthread_join()\fR call returns successfully with a non-null \fIstatus\fR argument, the value passed to \fBpthread_exit\fR(3C) by the terminating thread will be placed in the location referenced by \fIstatus\fR. 
.sp
.LP
If the \fBpthread_join()\fR calling thread is cancelled, then the target \fIthread\fR will remain joinable by \fBpthread_join()\fR. However, the calling thread may set up a cancellation cleanup handler on \fIthread\fR prior to the join call, which may detach the target \fIthread\fR by calling \fBpthread_detach\fR(3C). See \fBpthread_detach\fR(3C) and \fBpthread_cancel\fR(3C).
.SH RETURN VALUES
.sp
.LP
If successful, \fBpthread_join()\fR returns \fB0\fR. Otherwise, an error number is returned to indicate the error.
.SH ERRORS
.sp
.ne 2
.mk
.na
\fB\fBEDEADLK\fR\fR
.ad
.RS 11n
.rt  
A joining deadlock would occur, such as when a thread attempts to wait for itself.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 11n
.rt  
The thread corresponding to the given thread ID is a detached thread.
.RE

.sp
.ne 2
.mk
.na
\fB\fBESRCH\fR\fR
.ad
.RS 11n
.rt  
No thread could be found corresponding to the given thread ID.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityCommitted
_
MT-LevelMT-Safe
_
StandardSee \fBstandards\fR(5).
.TE

.SH SEE ALSO
.sp
.LP
\fBpthread_cancel\fR(3C), \fBpthread_create\fR(3C), \fBpthread_detach\fR(3C), \fBpthread_exit\fR(3C), \fBwait\fR(3C), \fBattributes\fR(5), \fBstandards\fR(5)
.SH NOTES
.sp
.LP
The pthread_join(3C) function must specify the \fIthread\fR \fBID\fR for whose termination it will wait.
.sp
.LP
Calling \fBpthread_join()\fR also "detaches" the thread; that is, \fBpthread_join()\fR includes the effect of the \fBpthread_detach()\fR function. If a thread were to be cancelled when blocked in \fBpthread_join()\fR, an explicit detach would have to be performed in the cancellation cleanup handler. The \fBpthread_detach()\fR function exists primarily for this purpose.