Steffen.Oeltze at Student.Uni-Magdeburg.DE
Sat Oct 5 05:46:13 EDT 2002
Alan McIntyre wrote:
> As far as passing function pointers goes, there is a difference
> between this:
> and this:
I receive an error during compiling saying that this is not a valid call
for a member-function.
> 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:
> void get_MousePos();
> Somebody please let me know if I'm totally clueless here; I don't want
> to give Steffen any bad info.
Thank you very much,
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