Thread: copying an object using memcpy

  1. #1
    char main() RoshanX's Avatar
    Join Date
    Mar 2003

    copying an object using memcpy

    hi all,

    I have a piece of code which suppose to reset the data members of a structure ( there are around 15 member variables ), this "clear" function gets called frequently and I want to make it run as fast as possible. Right now, I just use "assignment" operator. Can I use memcpy to copy over an initialized object over the object that I want to initialize ?. Will copying objects like this have any bad effects ?

    Thank you
    First there was God. He was quite lonely, so he created Dennis.
    Dennis was unimpressed with God.
    So, . . . God created Brian..........Khan Klatt

  2. #2
    The larch
    Join Date
    May 2006
    This might work, if the struct contains only simple types. It will have ill effects, though, if the struct contains pointers or something that contains pointers (e.g std::string).

    If the structure needs to be reset at the beginning of a loop, may-be you can construct it there. (May-be the compiler generates some extra good code, if it sees that an object with unchanging arguments is constructed over and over again.)

    By the way, it seems that assignment is faster (for a struct of 3 ints and a char).

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