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Have you ever wanted to use a pointer to a class method? This might be basic C++ but I couldn’t remember how to do it, and spent some time Googling and messing around to figure it out. So here’s the way:
To define a pointer to a class method:
returnval (myclass::*method)(parameters…)
For example:
char *(myclass::*pmethod)(int parm);
This defines a pointer named pmethod to a method of the myclass class. The method has a single int parameter and returns a char*.
To assign a value to the pointer:
pmethod = &myclass::method;
For example:
pmethod = &myclass::mymethod;
This sets pmethod to point to mymethod.
To call the class method:
(myobject.*method)(parameters…)
For example:
mychar = (myobject.*pmethod)(myint);
This calls the method pointed to by pmethod.
The pointer can itself be in a struct or class as well. For example:
struct { // processing table
char *name;
char *(myclass::*pmethod)(int parm);
} proctbl[] = {
{ “text”, &myclass::mymethod},
{ “text2”,&myclass::anothermethod}
};
This defines a table of structures with two entries, each of which has a method pointer. The function can then be called as follows:
mychar = (myobject.*proctbl[index].pmethod)(myint);
In this example, the pointer proctbl[index].pmethod identifies the method to be called.
Note that “::*” and “.*” are actually separate operators in C++. There is also a “->*” operator.
You might never need this, but just in case you do…
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