defining a function pointer which recieves a function pointer

This is a discussion on defining a function pointer which recieves a function pointer within the C Programming forums, part of the General Programming Boards category; Hi, maybe i can clarify what im trying to do a little bit. I want to make a program with ...

  1. #1
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    defining a function pointer which recieves a function pointer

    Hi, maybe i can clarify what im trying to do a little bit. I want to make a program with a modular design, and the way ive decided to do it is to have one central "request" function which is able to get the address of any function in any .dll which is loaded. However, for a .dll to get the address of this function, the "core" must load the .dll and call "initialize" which receives the function pointer to the "request". The problem is I cant find any example of a function pointer defined which receives a function pointer as an argument.

    Code:
    int (*initialize)(what goes in here) = NULL;  //what is the type of a function pointer??? thats what it all boils down to.
    &initialize = GetProcAddress(hInstLibrary, "initialize");

  2. #2
    and the hat of wrongness Salem's Avatar
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    Just use a couple of typedef's, it makes life so much easier

    typedef int (*fooFn)( int );
    typedef int (*barFn)( fooFn );


    Then
    barFn init = 0;
    init = GetProcAddress(hInstLibrary, "initialize");
    init( aFooFn );
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    Code:
    &initialize = GetProcAddress(hInstLibrary, "initialize");
    no & neccessary.

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    ill use the type defs, but im still curious as to how to define a pointer.

    as for the &, its technically the "correct" way to do it (so i believe), and in my opinion not using short hand makes code much more readable.

  5. #5
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    I think you're thinking of this:
    Code:
    int *i, j;
    i = &j;

  6. #6
    Deathray Engineer MacGyver's Avatar
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    The & is wrong imo.... You're dealing with a pointer, which holds an address. There's no reason to try to store something in the address of a pointer.

  7. #7
    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by *DEAD* View Post
    ill use the type defs, but im still curious as to how to define a pointer.

    as for the &, its technically the "correct" way to do it (so i believe), and in my opinion not using short hand makes code much more readable.
    You can do either.

    Short hand would be calling a variable "x" instead of "numElephantsInRoom." Leaving out an unnecessary ampersand isn't exactly conducting major surgery. I fail to see how its presence or absence in this case makes code any more/less clear.

    I'd say 50% of the code I've seen uses it when taking function addresses, the other half doesn't.

    EDIT: Also, your pointer type is something like:

    Code:
    int (*func)(int (*)(int));
    Pointer to function which takes (pointer to function which takes int returning int) returning int.
    Last edited by brewbuck; 07-04-2007 at 11:02 AM.

  8. #8
    Frequently Quite Prolix dwks's Avatar
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    However, for member function pointers in C++, you need to use &function. I think that's where the myth comes from. For ordinary function pointers, in both languages, function and &function are equivalent.

    Pointer to a Member Function
    http://www.newty.de/fpt/fpt.html#assign
    dwk

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