Often in API functions there are arguments that can be filled with a data type (like RECT, for graphics areas) or can be passed a NULL to use a default (such as the whole screen, for graphics areas). What exactly does this NULL mean? Does this mean that a ByVal ArgumentName As Long should be used when declaring the function, and then pass the value 0& (representing a pointer with the value of &h00000000) to the argument? Or does it mean that ByRef ArgumentName As Long should be used when declaring the function, and then pass the value 0& (representing a pointer to the memory location where the value &h00000000 is stored)?
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