From: "John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: c++ include file problems
Date: Sun, 18 Jan 1998 15:22:55 -0500
Organization: Two pounds of chaos and a pinch of salt.
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Kim Robert Blix wrote:
> 
> Im having a problem I cant find in any FAQ.
> 
> I have just installed djgpp, and everything seemed to work fine until
> i tried to compile a c++ program. It seems to me like the compiler
> cant find the c++ include files. I have attached a log of what
> happends here, I just want to mention that I have not edited
> djgpp.env. Any and all help is appreciated.

You're not linking the C++ libraries into your program.  It's not enough
to include the headers; the compiler must be told where to find the
actual code that the headers declare.  You may either add "-lgpp" to the
end of your command line, or substitute 'gxx' for 'gcc'.

The FAQ describes this problem:  "undefined reference to ..." in
chapters 8.1 and 8.2.  The 'readme.1st' file also tells you how to
compile C++ programs; evidently you forgot to read that far.

Additional comments:

> #include <iostream.h>
> 
> void main(void)
> {
>         cout << "Hello World";
> } /* main */

void main() is an illegal construct in C and C++.  main() must ALWAYS
return an integer; else you could cause major problems.  This is a rule
of ANSI C and any books that tell you otherwise are lying.

> e:\djgpp\code>gcc hello.cpp

I recommend the following command line:

   gxx -Wall -O -g -o hello.exe hello.cpp

This gives you maximum benefit of gcc's optimizations and warnings, and
would have told you about the 'void main' thing.  :-)  The '-o' option
also tells gcc what file to produce as output; otherwise it just makes
'a.exe'.

hth

-- 
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|      John M. Aldrich       | "Autocracy is based on the assumption|
|       aka Fighteer I       | that one man is wiser than a million |
|   mailto:fighteer AT cs DOT com   | men.  Let's play that over again,    |
| http://www.cs.com/fighteer | too.  Who decides?"   - Lazarus Long |
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