Subj : Re: Linux - waitpid portability
To   : comp.programming.threads
From : Marcin 'Qrczak' Kowalczyk
Date : Fri Feb 04 2005 08:50 am

sreenidishc@gmail.com writes:

> I ported this application on Solaris, Aix and HP UX. But On Linux,
> this design is not working because, it considers each thread as a
> distinct process. So the waitpid() called from the fifth thread could
> not reap the process status.

My 'man waitpid' on Linux says:

LINUX NOTES
       In  the  Linux kernel, a kernel-scheduled thread is not a distinct con-
       struct from a process. Instead, a thread is simply a  process  that  is
       created  using  the  Linux-unique  clone(2) system call; other routines
       such as the  portable  pthread_create(3)  call  are  implemented  using
       clone(2).   Before  Linux  2.4,  a  thread was just a special case of a
       process, and as a consequence one thread could not wait on the children
       of  another  thread,  even  when  the latter belongs to the same thread
       group.  However, POSIX prescribes such functionality, and  since  Linux
       2.4  a  thread  can,  and  by  default  will, wait on children of other
       threads in the same thread group.

-- 
   __("<         Marcin Kowalczyk
   \__/       qrczak@knm.org.pl
    ^^     http://qrnik.knm.org.pl/~qrczak/

.