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set_tid_address.2: Use "thread" rather than "process" in DESCRIPTION 

Reported-by: Rich Felker <dalias@libc.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2014-07-06 09:13:40 +02:00
parent b701f72de4
commit b5693a3854
1 changed files with 10 additions and 10 deletions
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20
man2/set_tid_address.2
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@ -32,14 +32,14 @@ set_tid_address \- set pointer to thread ID
.BI "long set_tid_address(int *" tidptr );
.fi
.SH DESCRIPTION
For each process, the kernel maintains two attributes (addresses) called
For each thread, the kernel maintains two attributes (addresses) called
.I set_child_tid
and
.IR clear_child_tid .
These two attributes contain the value NULL by default.
.TP
.I set_child_tid
If a process is started using
If a thread is started using
.BR clone (2)
with the
.B CLONE_CHILD_SETTID
@ -51,11 +51,11 @@ argument of that system call.
.IP
When
.I set_child_tid
is set, the very first thing the new process does
is writing its PID at this address.
is set, the very first thing the new thread does
is to write its thread ID at this address.
.TP
.I clear_child_tid
If a process is started using
If a thread is started using
.BR clone (2)
with the
.B CLONE_CHILD_CLEARTID
@ -69,25 +69,25 @@ The system call
.BR set_tid_address ()
sets the
.I clear_child_tid
value for the calling process to
value for the calling thread to
.IR tidptr .
.LP
When a process whose
When a thread whose
.I clear_child_tid
is not NULL terminates, then,
if the process is sharing memory with other processes or threads,
if the thread is sharing memory with other threads,
then 0 is written at the address specified in
.I clear_child_tid
and the kernel performs the following operation:
futex(clear_child_tid, FUTEX_WAKE, 1, NULL, NULL, 0);
The effect of this operation is to wake a single process that
The effect of this operation is to wake a single thread that
is performing a futex wait on the memory location.
Errors from the futex wake operation are ignored.
.SH RETURN VALUE
.BR set_tid_address ()
always returns the PID of the calling process.
always returns the caller's thread ID.
.SH ERRORS
.BR set_tid_address ()
always succeeds.