From:	Thomas Demmer <demmer AT lstm DOT ruhr-uni-bochum DOT de>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: HELP: Linker hates me!
Date:	Tue, 05 May 1998 08:57:15 +0200
Organization:	Lehrstuhl fuer Stroemungsmechanik
Lines:	39
Message-ID:	<354EB84B.C911FF38@LSTM.Ruhr-UNI-Bochum.De>
References:	<354E35F1 DOT 4EE71278 AT sprynet DOT com> <6ilcql$8e3$1 AT news DOT luth DOT se>
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Martin Str|mberg wrote:
[...]
> 
> Well  I don't have any problems with that code:
> descartes:/tmp> gcc -Wall main.cc stuff.cc
> main.cc:3: warning: return type for `main' changed to integer type
> 
> However this is more interresting:
> descartes:/tmp> gcc -Wall main.cc stuff.c
> main.cc:3: warning: return type for `main' changed to integer type
> /tmp/cca125441.o: In function `main':
> /tmp/cca125441.o(.text+0x8): undefined reference to `foo(void)'

Well, C++ does name mangling, so 
int foo(void);
is turned into something like
_foo_iv
by the C++ compiler to enable type safe linking. 

The C compiler just turns this into _foo. To make your second example
work replace the prototype in main by
extern "C" {
   int foo(void);
}

-- 
Ciao
Tom

*************************************************************
* Thomas Demmer                                             *
* Lehrstuhl fuer Stroemungsmechanik                         *
* Ruhr-Uni-Bochum                                           *
* Universitaetsstr. 150                                     *
* D-44780  Bochum                                           *
* Tel: +49 234 700 6434                                     *
* Fax: +49 234 709 4162                                     *
* http://www.lstm.ruhr-uni-bochum.de/~demmer                *
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