fusion at thuule.pair.com
Fri Oct 4 19:48:58 EDT 2002
As far as passing function pointers goes, there is a difference between
The first one passes the result of a call to function() into the
SetSomething method, while the second one passes the address of the
'my_function' function into the SetSomething method. I think the '&' in
the second example isn't necessary in the eyes of some (most?)
compilers, but having it there doesn't do any harm as far as I know.
The second example is the one you want in your particular case.
As for passing a C++ class method in as the parameter to
SetLeftButtonPressMethodArgDelete, I'm not exactly sure about the
'proper' way to do that, since it appears to be expecting a plain C
function. What kind of compiler error are you getting?
I don't have the VTK source on my machine here at home right now, so I'm
kind of in the dark as to the usage/behavior of
SetLeftButtonPressMethodArgDelete, but I'm wondering if the reason the
it expects a pointer to a function with a void* parameter is so that
class methods can be given to it. If I recall correctly, isn't the
pointer to the object pushed onto the stack (kind of like an invisible
first parameter) when calling class methods? If that's the case,
perhaps the get_mousePos(void*) method in Steffen's example could be
passed if it was declared like this:
Somebody please let me know if I'm totally clueless here; I don't want
to give Steffen any bad info.
Steffen Oeltze wrote:
> Alan McIntyre wrote:
>> The "void(*f)(void *)" parameter is a pointer to a C function that
>> looks like this:
>> void func(void *);
>> How much that helps you out I don't know. If you could post some more
>> code I can try to help, even though I haven't done much with VTK in C++.
> The function I use is:
> void SliceView::get_mousePos(void *)
> The function declaration is:
> void get_mousePos(void *);
> The assignment (which doesn't work) of the function:
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