Date: Sun, 8 Jul 2001 06:44:44 -0500 From: David Leimbach <leimbacd@bellsouth.net> To: questions@freebsd.org Subject: Re: Passing data in C++ via stdin without waiting for the new process to complete Message-ID: <20010708064444.A519@mutt.home.net> In-Reply-To: <3B484403.1BA9A21D@jak.nl>; from arjan@jak.nl on Sun, Jul 08, 2001 at 01:29:07PM %2B0200 References: <114577608557.20010708130014@buz.ch> <3B484403.1BA9A21D@jak.nl>
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also all the different versions of exec:
man:
execl, execlp, execle, exect, execv, execvp=20
Fork makes a copy of the current process. If you want to run something
else after a fork do an exec.
system does a fork, exec and wait. you seem to want everything but the
wait. :)
Dave
On Sun, Jul 08, 2001 at 01:29:07PM +0200, Arjan Knepper wrote:
> read :
>=20
> man -a 2 fork
> man -a 2 rfork
> man -a 2 vfork
> man -a 2 wait
> man -a 2 _exit
> man -a 3 exit
> man -a 2 dup dup2
>=20
> Good luck
> Arjan Knepper
>=20
> P.S Buy the book : "Advanced Programming in teh UNIX environment" by
> W.R.Stevens ISBN:0-201-56317-7 and maybe his other books about "Unix
> Network Programming" as well.
> (Saw those for sale on the streets in NY !!)
>=20
> Gabriel Ambuehl wrote:
>=20
> > -----BEGIN PGP SIGNED MESSAGE-----
> >
> > Hello,
> >
> > I wonder how I could efficiently achieve to pass data via stdin to a
> > new process spawned by the current one without having the parent
> > process waiting for the child to complete. I just want to spawn the
> > child, pass the data to it and then forget about it, no matter how
> > long it takes for the child to complete.
> >
> > popen() doesn't appear to be a suitable tool for this kind of work as
> > the manpage says:
> >
> > The pclose() function waits for the associated process to
> > terminate and
> > returns the exit status of the command as returned by wait4().
> >
> > which means that the parent is blocked til the client finishes.
> >
> > system("echo data | some_app");
> > does work, but the parent process still is blocked till the child
> > finishes and I don't think it's the most efficient of all ideas to
> > first spawn a shell (although popen() appears to be doing this as
> > well), then spawn an instance of echo just to get the data where it
> > should be and then spawn the third process to do the actual work.
> >
> > Any comments would greatly be appreciated.
> >
> > TIA & best regards,
> > Gabriel
> > =04
> >
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>=20
>=20
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