Thread: multiple files

  1. #1
    Registered User
    Join Date
    Jun 2003

    multiple files

    My program uses several global variables to handle things that a lot of functions will be using and changing ( HDCs, HWNDs, etc ) The unfortunate thing is that these functions are spread across many differant files. How can I declare a global variable in a header file without redefinition errors?
    Last edited by YingPar; 06-04-2003 at 06:04 PM.

  2. #2
    Code Goddess Prelude's Avatar
    Join Date
    Sep 2001
    Use inclusion guards with the preprocessor:
    #ifndef DEFS_H_
    #define DEFS_H_
    // Definitions go here
    My best code is written with the delete key.

  3. #3
    Registered User
    Join Date
    Apr 2003
    You can declare global variables in a .cpp file like this:

    double pi=3.14;

    and then use

    extern int pi;

    in the other .cpp files. If your globals are declared as const, then they must be declared with the extern key word as well, like:

    extern const double pi = 50;

    so they are accessible from another .cpp file:

    extern const double pi;

  4. #4
    Registered User
    Join Date
    Jun 2003
    Thanks, it seems to be working now

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