Path: utzoo!mnetor!uunet!husc6!hao!oddjob!gargoyle!ihnp4!laidbak!daveb
From: daveb@laidbak.UUCP (Dave Burton)
Newsgroups: comp.lang.c
Subject: Re: exit(main(argc,argv,env));
Message-ID: <1284@laidbak.UUCP>
Date: 18 Dec 87 06:13:14 GMT
References: <10875@brl-adm.ARPA>
Reply-To: daveb@laidbak.UUCP (Dave Burton)
Organization: is pretty bad/My method of
Lines: 29

In article <10875@brl-adm.ARPA> ADLER1%BRANDEIS.BITNET@CUNYVM.CUNY.EDU writes:
>I was looking through the file crt0.c in the GNU emacs source code and
>found the command
>
>exit(main(argc,argv,env));
>
>which I find puzzling. I thought that one was supposed to give exit a
>number for an argument. What does the above command do and why would
>anyone want to do it that way ?
>
>ADLER1@BRANDEIS.BITNET

Actually, "main(...)" DOES give exit() an integer argument.
Remember, any function without a type declaration in C is implicitly
a function returning int.

This line of code simply starts the C program at the symbol "main",
passing the usual arguments to it. When main returns, an integer value
is pushed on the stack for the exit().

I don't have the emacs source, so I don't know exactly what main()
returns to exit(). If no explicit return is given, the value returned
is undefined. If main() quits with an exit() call, I believe the
exit(main()) will get the argument from the main(){ ... exit(x); }.
-- 
--------------------"Well, it looked good when I wrote it"---------------------
 Verbal: Dave Burton                        Net: ...!ihnp4!laidbak!daveb
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