[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: vfork()

"vfork" was intended to be used when the subprocess was going shuffle file
descriptors, cd .. directory , etc. - and then "exec".  it only copy the u.
area (same resources the parent process had).

----- Original Message -----
From: "Javier Guerra" <listasJGG@eos.com.pe>
To: <kernelnewbies@nl.linux.org>
Sent: Sunday, February 09, 2003 9:56 PM
Subject: Re: vfork()


> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> MAASK Group wrote:
> > >Vfork is a combination of fork() and exec().
> >
> > I am confused. The programmer explicitly has to call exec() after a
> > vfork(). right?
>
> right, vfork() isn't a combination of fork() and exec(), more exactly,
it's a
> version of fork() to be used only when immediatly followed by a exec()
> so, instead of writing
>
> if (! fork ())
> exec (...);
>
> you could write
>
> if (! vfork ())
> exec (...);
>
> and avoid the copying of the process segment that would be overwritten by
> exec().  in modern OSs, the process is marked copy-on-write, so it's just
as
> fast, without the restrictions.  that's why it's man page tells you not to
> use it anymore.
>
> - ------
> Javier
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.2.1 (GNU/Linux)
>
> iD8DBQE+Rn3HsIoGnxsRK/ERAmzmAJ0YLEju/TRGLnX8asM3vEN/MgMVXQCgpdUL
> B4WhKo2sgxVbxDkGq/QPbLo=
> =Bxlb
> -----END PGP SIGNATURE-----
>
> --
> Kernelnewbies: Help each other learn about the Linux kernel.
> Archive:       http://mail.nl.linux.org/kernelnewbies/
> FAQ:           http://kernelnewbies.org/faq/
>
>

--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive:       http://mail.nl.linux.org/kernelnewbies/
FAQ:           http://kernelnewbies.org/faq/