Thanks a lot for the reference, derby (and ++ for your nitpicking). I have a small difference, though...

Actually, mmap() does not allocate memory. What it does is map pages belonging to a file, probably from the buffer cache, into your process' private address space. Certainly it is a neat trick, but might have undesired side effects when competing with file-related resources in the same machine, specially with a static buffer cache.

They will "return" the memory to the OS because the memory was not originally allocated to your process. I am glad to see certain implementations of malloc() and free() taking advantage of this.

Best regards

-lem, but some call me fokat