Thread: Eliminate Padding using normal variables (not structures)

  1. #1
    Registered User
    Join Date
    Jun 2020

    Eliminate Padding using normal variables (not structures)

    Yesterday i learned what padding is, i know it happens in structures but iīve also realized it happens when you declare variables that donīt have the same size, for example:
    int a;
    char b;
    int c;
    I understand why this happens, and i know that you can activate #pragma pack() to disable padding in structures; just because Iīm curious, can you eliminate padding with how all variables are allocated?

  2. #2
    C++ Witch laserlight's Avatar
    Join Date
    Oct 2003
    You probably already know this, but just in case: re-ordering the declarations to reduce the need for padding for alignment would generally be something to reach for before something like #pragma pack, and this should apply for variables not within a struct declaration too.

    On the other hand, I don't think this usually comes up because the savings are unlikely to be worth the effort, whereas it can matter for structs as there could be an array of them, so the wasted bytes easily add up.
    Last edited by laserlight; 06-06-2020 at 08:36 PM.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
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