Hello Anton, Joern,
please don't mix a ptr-to-function and a ptr-to-member-function.
The former is just the address of a function. The later is
a structure containing
the function address for non-virtual functions
the vtable index for virtual functions
the this pointer offset
The representation of the structure is implementation specific,
and does for some compilers even depend on whether the class
has virtual functions or multiple inheritance or not.
All this is needed to calculate
the actual entry point address
and the effective this pointer
when the ptr-to-member-function is finally used in a call.
In cases like multiple inherited base classes with virtual
functions in virtual base classes things get nontrivial here!
Inspect the C++ lanuage definition for the allowed conversions
and casts of a ptr-to-member-function, and you'll see, there are
very few.
In the light of all this I wonder portable Joern's code example is.
Beyond that, the code
TThread* mythread= new TThread("My Thread",
(void(*) (void *)) &Myclass::myfunction,
(void*) &Myclass);
will probably not give the desired result if Myclass uses
multiple inheritance and myfunction is from one of the base
classes (that's why the PTMF struct may contain a this offset).
With best regards, Walter
--
Walter F.J. Mueller Mail: W.F.J.Mueller@gsi.de
GSI, Abteilung KP3 Phone: +49-6159-71-2766
D-64291 Darmstadt FAX: +49-6159-71-2989
WWW: http://www-kp3.gsi.de/www/kp3/people/mueller.html
PGP: http://www-kp3.gsi.de/~mueller/pgp.shtml
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