Thread: Where are the functions?

  1. #1
    Registered User
    Join Date
    Dec 2002

    Where are the functions?

    I'm confused where the actual code is for a function from an included header. For example, if I include math.h, then i can use the sqrt() function(among others), but where is sqrt()'s actual code, and where in math.h does it tell the compiler where the code is?

  2. #2
    Registered User
    Join Date
    Aug 2003
    was tryin to find a previous post that explained ur question but i can't seem to find it.

    anyway, the header files only contain (function wise anyway) only function prototypes. Thats all the compiler needs to know at compile time, just each function signature. The actual code for the functions are in binary in object files. The linker links the functions from each object file to the other.

    So when u compiler say a .cpp file with printf, and compile it, it is compiled into an object file. This file is in binary, but the actual function names still exists in the file. The linker sees the function name and looks for it in the other object file. It then links the name and produces a full executable (entirely binary).

    these object files are .lib file (library file). The ones that you would produce using say gcc would be .o (object) files.
    Last edited by Kyro; 11-05-2003 at 11:41 PM.

  3. #3
    Registered User
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    Dec 2002
    Is it possible to get the C/C++ code for the object library files, or is it written in assembly or not distributed?

  4. #4
    C++ Witch laserlight's Avatar
    Join Date
    Oct 2003
    I think this site's FAQ deals with this:

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