Обсуждение: function compiled with g++

Why the same function writen in C, compiled with gcc works OK, but compiled
with g++, doesn't even load? Not mentioning those written in C++.

i.e. loader reports undefined symbol: pg_detoast_datum__FP7varlena or some
other undefined symbol...

I would actually need to know should I forget C++ for writing functions or
am I just doing something wrong ?

Thanks.
Boris

> Why the same function writen in C, compiled with gcc works OK, but compiled
> with g++, doesn't even load? Not mentioning those written in C++.
> i.e. loader reports undefined symbol: pg_detoast_datum__FP7varlena or some
> other undefined symbol...

C++ compilers do "name mangling" to allow function overloading. If you
are going to call a C++ routine from C or most other languages, you need
to wrap the declaration for the called function in the following:

  extern "C" {
    retval your_function_here(arg1,arg2);
  }

hth

                       - Thomas

C++ mangles the symbols for linking, i.e. a function named "foo" might not be
the symbol "foo". Try using the 'extern "C" { ... }' to make the symbols keep
their names like in C.

Hope this helps,
Jeff Davis

On Sunday 23 September 2001 11:03 pm, you wrote:
> Why the same function writen in C, compiled with gcc works OK, but compiled
> with g++, doesn't even load? Not mentioning those written in C++.
>
> i.e. loader reports undefined symbol: pg_detoast_datum__FP7varlena or some
> other undefined symbol...
>
> I would actually need to know should I forget C++ for writing functions or
> am I just doing something wrong ?
>
> Thanks.
> Boris
>
>
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