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From: mwjester@wsuiar.uucp (loki)
Newsgroups: comp.lang.c
Subject: Forward declaration (was Re: Novice question.)
Message-ID: <427.2742a06f@wsuiar.uucp>
Date: 15 Nov 90 19:04:31 GMT
References: <336@brat.UUCP> <3838@vela.acs.oakland.edu> <1990Nov14.010511.7241@ux1.cso.uiuc.edu> <1990Nov14.143802.23021@noose.ecn.purdue.edu>
Organization: Wichita State Univ., Wichita KS
Lines: 37

In article <1990Nov14.143802.23021@noose.ecn.purdue.edu>,
 longshot@monkey.ecn.purdue.edu (The Knight Guard) writes:
>>	"extern" means that the variable is global, and was declared in a
>>separate .c file.  If your program occupies only 1 file, you will never
>>use this.
>>
>>John Gordon
> 
> 	Not true here...  Our cc seems to require that all functions/procedures
>   be defined before the main block.  The way around this is to extern all 
>   functions before main...  Dunno if this is just our compiler, anyone else
>   seen this?  Any ideas of why?

I'm not sure what compiler/environment you're using, but you will often find
that a function used in main() is assumed to return type int unless the 
compiler has reason to believe otherwise.  When the function appears later
in the text and returns a different type, the compiler accuses you of
redefining it.

You should be able to work around this by defining the return type expected
within main(), e.g.

	main()
	{
		int a,b;
		double bogus();
		.
		.
		.
	}

The above just lets the compiler know about bogus()'s return type, and you
needn't specify the parameters to the function, just its type.

Hope this helps.

Max J.