How to use the API file operation, realize the release documents the tail part of the space, namely after writing the file size, less than written before?

I now want to operate a file already exists, assuming that the file size of 3 k,
And I want to write the contents of the accounts for only 2 k,
This in FileWrite API functions, such as how to realize?

I know that after the first remove to Create,
But it should be low efficiency,
I want to delete the end-of-file spare parts directly, how should do?

CodePudding user response:

CreateFile to open the file, after you have written in FileWrite, reoccupy Windows API: SetEndOfFile, finally the CloseHandle