How can I create a RAM disk programmatically?

I am not looking for a code that invokes a command line utility, which does the trick. I am actually interested to know the API used to create a RAM disk.

EDIT

Motivation: I have a third party library which expects a directory name in order to process the files in that directory in a certain way. I have these files zipped in an archive. I wish to extract the archive into a RAM disk and pass the third party the path to the respective directory on that RAM disk. As you can see, memory mapped files are of no use to me.