🚀 go-pugleaf

In article <2q67fpINNgv5@eccdb1.pms.ford.com> poorman@cc4032.pms.ford.com (Glenn M. Poorman) writes:
>In article <2q65gv$oln@bigblue.oit.unc.edu>, brandon@uncvx2.oit.unc.edu (Brandon Van Every) writes:
>|> Paul Durbin (pauld@verdix.com) wrote:
>|> : I attempt to use a member function as callback but all three arguments (to the
>|> : callback) are garbage. If I make it a friend then the arguments are correct,
>|> : but then I can't get to the class data, without reference thru an instance of
>|> : the class and I don't want the data to be static.
>|> 
>|> : So, what is causing this problem? 
>|> 
>|> Motif is based on C, not C++.  You have to use "extern C" linkage for any of
>|> your callbacks.  You can't register any C++ function directly.  You have to
>|> write a plain C front end for anything you want to have callbacked.
>
>Actually the function does not have to have "extern C" linkage.  It just
>can't be a non-static member function.
>
>-- 

    The callback function really should be an "extern C" function if
you want portability among current and possible future C++ compilers.
Remember, C++ and C are different languages.  There is nothing in the
definition of C++ that requires that a C++ compiler use the same 
methods for passing function parameters as are used by C.  The exception
is for an "extern C" function.

Glenn Pinkerton
glp@csn.org