CreateCompatibleBitmap()

Is it okay to pass zero to this function as the hdc? I've seen some bitmap classes that load an image using LoadImage, and then create an hdc using CreateCompatibleDC, put 0 is passed to this function. I've also seen a blank bitmap created using CreateCompatibleBitmap(), and then the DC is created using CreateCompatibleDC(), but a value is required other than zero. What is the purpose of passing a value to CreateCompatibleDC()? When and when can't 0 be used?

thanks,
jmiller

You can pass NULL, but then you'll get a black/white bitmap/dc. The value passed to the two functions is the dc that the new object should be compatible to.