redirecting standard i/o from an exec'ed programme

[Maarten Litmaath]

In article <410 at sun13.scri.fsu.edu>,
	mayne at VSSERV.SCRI.FSU.EDU (William (Bill) Mayne) writes:
)...
)    /* Close unused pipes */
)    close (TOCHILD);
)    close (FROMCHILD);
)    /* Change stdin and stdout to pipe */
)    close(0);
)    dup(FROMPARENT);

     close(FROMPARENT);		/* !!! */

)    close(1);
)    dup(TOPARENT);

     close(TOPARENT);		/* !!! */

I've deleted the rest of the code, but there were still a few other places
where calls to close() should be added.
Always close every unused file descriptor (esp. when dealing with pipes),
else you will get bitten one day; example scenario:

	- the child exits
	- the parent reads from the pipe to the child
	- the parent still has the write side of the pipe open
	- the read hangs...
--
   "UNIX was never designed to keep people from doing stupid things, because
    that policy would also keep them from doing clever things."  (Doug Gwyn)