Re: [PATCH] add sched_getcpu

[Szabolcs Nagy <nsz@port70.net>]

* Tomasz Sterna <tomek@xiaoka.com> [2016-03-02 21:46:53 +0100]:
> W dniu 01.03.2016, wto o godzinie 17???34 -0500, u??ytkownik Rich Felker
> napisa??:
> > syscall(SYS_exit
> > SYS_exit cannot be used safely unless you have a single-threaded
> > program, and in that case you can use _exit (SYS_exit_group).
> 
> How should I properly terminate current task then?
> 

pthread_exit

> > > syscall(SYS_gettid
> > For glibc it's been controversial whether to expose tids as a public
> > API, since it pokes through the pthread abstraction and imposes a 1:1
> > threads implementation.
> 
> I am implementing a threading and mutex API that is different to
> pthread. (Still 1:1 though.)
> Using pthread to do this proved to be cumbersome, but using native
> Linux abstractions turned out to be pretty straightforward.
> 

that's not possible in c

the semantics (memory model, libc internals..) assume
that threads can only be created by the c runtime.

in theory you can create you own threads, but you have
to know what you are doing (no libc calls, no tls)
but then you are implementing your own libc

> > syscall(SYS_tgkill
> > tgkill also requires tids to be exposed an potentially has other
> > issues, and doesn't seem to offer anything that pthread_kill doesn't.
> 
> As above - using pthreads is not the good way to do it in my case.
> 

what you are doing is undefined behaviour.