Subj : Re: How to pass class-member function to pthread_create(....)?
To   : comp.programming.threads
From : Vyacheslav Kononenko
Date : Mon Jul 18 2005 01:50 pm



Torsten Robitzki wrote:
> Vyacheslav Kononenko wrote:
>
> >
> > Chris Thomasson wrote:
> >
> >>>>Unfortunately extern "C" is necessary if your interested in creating
> >>>>"correct code"...
> >>>
> >>>The problem is using extern "C" does _NOT_ make 100% correct code
> >>>either. It could be safer to do that. But could be safer is different
> >>>than correct/incorrect statements showed here.
> >>
> >>I would argue that it is "correct" to use extern "C" for the functions you
> >>pass to a pthreads library; pthreads is a C library after all...
> >
> >
> > extern "C" does not gurantee that your C++ function would be correctly
> > callable from any C code.
>
> So what's the point of declaring a function extern "C" other then make
> it callable from C?
But make it callable from C is different than guarantee that _ANY_ C
code compiled by _ANY_ C compiler or C++ compiler in C mode with _ANY_
set of options will call extern "C" function correctly, isn't it?

> It might work. But why would one gamble and depend on something that
> might work if there is an easy approach that is required to work because
> there are specifications that guaranties that this approach will work?

There is no such specifications that the problem. You have to know that
your C library compiler code is compatible with C++ compiler generated
code anyway. And you can know if it is safe to call extern "C++"
linkage from the C library as well.
> 
> regards
> Torsten

Regards,
Vyacheslav

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