Appendix B. Pointers
CopyMemory
is
used a great deal throughout the course of this book to copy memory
from one location to another. Without this function, it would be
impossible to use pointers in Visual Basic. Since the function does
exist, it is possible to write some very dangerous VB code. A short
course on CopyMemory and pointers is definitely
in order.
CopyMemory
There is really no function called CopyMemory.
CopyMemory is merely an alias for the Win32
function RtlMoveMemory. Bruce McKinney, the
author of Hardcore Visual Basic (Microsoft
Press), was probably the first to use the alias
CopyMemory. Now it is quite common to see
RtlMoveMemory declared in this fashion. Its
syntax (as reflected in a Visual Basic Declare
statement) is:
Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
(pDest As Any, pSource As Any, ByVal ByteLen As Long)where pDest is a pointer to the starting
target address to which data is to be copied,
pSource is a pointer to the starting
address from which data is to be copied, and
ByteLen is the number of bytes to be
copied.
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