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An MFC class to encapsulate Memory Mapped Files





CMemMapFile was designed to be an MFC class to encapsulate Memory Mapped Files.

Memory mapping is a powerful mechanism Win32 provides to implement shared memory and also to access files though a simple memory pointer without having to implement your own home brewed buffering mechanisms. As an example its as simple as calling

void* lpData = mmf.Open();
CharUpperBuff(static_cast(lpData), static_cast(mmf.GetLength()));

to convert a file (of any length) to upper case.

Areas where you might find this of interest include very large database files with fixed records, audio processing, string operations and image processing.

The other side of memory mapped files is to implement shared memory. As you will probably know, Win32 puts each process into its own address space, thus making it impossible to pass ordinary pointers across process boundaries. With memory mapped files you get back this very useful mechanism.
Last updated on January 30th, 2014