Path: utzoo!utgpu!water!watmath!clyde!rutgers!mit-eddie!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: system
Message-ID: <7152@brl-smoke.ARPA>
Date: 21 Jan 88 16:07:15 GMT
References: <127@dcrbg1.UUCP> <452@picuxa.UUCP> <3920@sigi.Colorado.EDU>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 12

In article <3920@sigi.Colorado.EDU> swarbric@tramp.Colorado.EDU (SWARBRICK FRANCIS JOHN) writes:
>Just curious, but what do fork() and wait() do?  I have Turbo C, and it has
>execlp(), but neither of the other two.  Does it have something to do with
>the fact that UNIX is multiuser, while MS-DOS is not?

Yes, exactly.  fork() creates a duplicate process image that shares the
same open files; it returns 0 in the "child" process and the child's ID
number in the "parent" process, both of which are then concurrently
executing.  exec() simply overlays a process image from a file on top
of the currently executing one, then starts execution at its new entry
point; the process ID remains unchanged.  The combination of the two
effectively "spawns" a new subprocess.