.cpp linking problem

[Jon M. Hanson]

It sounds like you're getting the same header file included multiple  
times. If you look at the system header files you will see something  
like the following:

#ifndef _STDIO_H
#define _STDIO_H

[Header file code here]

#endif

So the first time stdio.h is included the header file code will be  
compiled. The second time something tries to include stdio.h, _STDIO_H  
is now defined so the header code is skipped thus avoiding the  
multiple includes. Try this with your header file(s) to see if it helps.

---
Jon M. Hanson (N7ZVJ)
Weblog: http://the-hansons-az.net/wordpress/
Homepage: http://the-hansons-az.net/
Jabber IM: jon at the-hansons-az.net



On Feb 14, 2009, at 8:03 PM, unixprgrmr01 at gmail.com wrote:

> I am trying to link library xy.a composed of x.o containing function  
> x() and y.o containing function y() with d.o giving executable d
>
> I call both x() and y() from d.cpp.  When I comment out the function  
> call to y() in d.cpp it links just fine with library xy.a giving  
> executable d BUT when I uncomment the function call to y() I get  
> duplicate variable declaration errors.
>
> Note that I need x.o and y.o in a library because I also link them  
> with e.o to give executable e . Both x() and y() are called from  
> both d and e executables.
>
> I use the same custom include files in x.o y.o d.o and e.o. I am  
> getting duplicate variable errors from the variables declared in  
> these custom include files.
>
> I also include standard include files such as <stdio.h> and <math.h>  
> etc. etc. in all 4 .o's but I don't get duplicate variable errors  
> from these.
>
> I am #ifndef ing the entire include file just as is done with  
> <stdio.h> etc. What am I doing wrong, that at link time I get  
> duplicate variable errors?
>
> Thanks for your help!
>
> -- 
> Best Regards,
> Lynn P. Tilby
> Ph: 480 632-8635
> unixprgrmr01 at gmail.com
>
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