Re: problem linking program containing bison-generated parser

[Alfonso Urdaneta]

Volker Wegert wrote:
> Alfonso Urdaneta <address@hidden> writes:
>
> > > Works without problems, now :-)
> >
> > Do you know why, or don't really care once it works ?
>
>
> I don't know why, and yes, I'd like to know. :-)
>
> Thanks in advance
>   Volker

C++ allows you to create functions with the same name and different 
arguments.  To keep them straight, the functions are internally 
represented as a glob of the function name the args, the phase of the 
moon, and your shoe size.  This is called "name mangling".

C does not.

When you call a C function from a C++ program, the compiler does not 
know that its a C function, so if you call foo, at link time it actually 
looks in the symbol table for a function called 
foo_no_args_and_the_author_likes_cheese(). Since there is of course no 
function like that, because foo is a c function, you will get link errors.

By putting the "extern C" bit, you are telling the compiler to not 
mangle the name before it tries to find it in the symbol table and your 
linker errors go away.



--
alfonso e. urdaneta
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