Re: Porting vfork()

Horst von Brand (vonbrand@inf.utfsm.cl)
Mon, 11 Jan 1999 11:28:04 -0300

Tim Smith <tzs@tzs.net> said:
> On Sun, 10 Jan 1999, Torbjorn Lindgren wrote:
> > The requirements are basically (paraphrased):
> > * Don't modify any data other than a variable of type pid_t used to store
> > the return value from vfork()
> > * Don't return from the function in which vfork() was called.
> > * Don't call any functions before successfully calling _exit(),or one of
> > the exec family of functions.

> That last requirement seems overly stringent. I'd expect the child to be
> able to (and need to) call open, close, dup, fcntl, etc., to deal with
> IO redirection before calling exec.

Then you can't use vfork(2), you must use fork(2).

All this trouble to shave off a fraction of a percent on a libc build. I
just don't get it.

[The BSD folks claim "a few seconds less in a libc build", let's make that
5 seconds out of 30 minutes (this should be generous). That makes a full
0.27%.]

-- 
Dr. Horst H. von Brand                       mailto:vonbrand@inf.utfsm.cl
Departamento de Informatica                     Fono: +56 32 654431
Universidad Tecnica Federico Santa Maria              +56 32 654239
Casilla 110-V, Valparaiso, Chile                Fax:  +56 32 797513


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