Creating a file of arbitrary size using Windows C++ API

Question

I would like to create a file of arbitrary size using the Windows C/C++ API. I am using Windows XP service pack 2 with a 32 bit virtual address memory space. I am familiar with CreateFile.

However CreateFile does not have a size arument, The reason I want to pass in a size argument is to allow me to create memory mapping files which allow the user to access data structures of predetermined size. Could you please advise of the proper Windows C/C++ API function which allow me to create a file of arbritrary predetermined size? Thank you

Answer 1

You CreateFile as usual, SetFilePointerEx to the desired size and then call SetEndOfFile.

Answer 2

To do this on UNIX, seek to (RequiredFileSize - 1) and then write a byte. The value of the byte can be anything, but zero is the obvious choice.