What are the exact use of CreateFileMapping & MapViewOfFile

[swell]

I'm reading the code of dnlib and I was wondering the exact purpose of CreateFileMapping & MapViewOfFile primitives?

What are the advantages of using these?

Thanks guys!

[Extreme Coders]

The main advantage is that you do not need a buffer, to operate on the file.

You can directly access the file contents as if it was located directly in your own address space.

 

Read up on MSDN, it is already explained there: https://msdn.microsoft.com/en-us/library/windows/desktop/aa366556(v=vs.85).aspx

Also read this SO post.

[Peter Ferrie]

It allows the file to be accessed directly (including writing) as an array of bytes in memory.It replaces this sequence:

VirtualAlloc() -> region

SetFilePointer()

ReadFile()

update region

SetFilePointer()

WriteFile()

SetFilePointer()

ReadFile()

update region

SetFilePointer()

WriteFile()

...

SetFilePointer()

ReadFile()

update region

SetFilePointer()

WriteFile()

with this one:

CreateFileMapping()

MapViewOfFile() -> region

update region

update region

...

update region

Edited October 9, 2015 by Peter Ferrie