Re: [PATCH] Linux: Add gettid system call wrapper [BZ #6399]

[Florian Weimer <fweimer at redhat dot com>]

* Joseph Myers:

> On Wed, 5 Dec 2018, Florian Weimer wrote:
>
>> This commit adds gettid to <unistd.h> on Linux, and not to the
>> kernel-independent GNU API.
>
> This is missing a NEWS entry,

I plan to add this:

+* On Linux, the gettid function has been added.

> and documentation (which seems particularly 
> important in this case, to discuss what a tid is and is not and what 
> interfaces it can be used with).

I can put more details into the comment:

/* Return the kernel thread ID (TID) of the current thread.  The
   returned value is not subject to caching.  Most Linux system calls
   accept a TID in place of a PID.  Using the TID to change properties
   of a thread that has been created using pthread_create can lead to
   undefined behavior (comparable to manipulating file descriptors
   directly that have not been created explicitly).  Note that a TID
   uniquely identifies a thread only while this thread is running; a
   TID can be reused once a thread has exited, even if the thread is
   not detached and has not been joined.  */

I do not want to contribute to the manual at this point.

I would rather improve the manpages project documentation and clarify
there when a PID is actually a TID and deals with what are essentially
task properties.

Should we have a separate conversation about the future of the manual?

Thanks,
Florian