Moving and Replacing Files
Before a file can be copied, it must be closed or opened only for reading. No thread can have the file opened for writing. To copy an existing file to a new one, use the CopyFile or CopyFileEx function. Applications can specify whether CopyFile and CopyFileEx fail if the destination file already exists. If the file does exist and is open, it must have been opened with applicable sharing permissions. For more information, see CreateFile.
The CopyFileEx function also allows an application to specify the address of a callback function (see CopyProgressRoutine) that is called each time another portion of the file has been copied. The application can use this information to display an indicator that shows the total number of bytes copied as a percent of the total file size.
The ReplaceFile function replaces one file with another file, with the option of creating a backup copy of the original file. The function preserves attributes of the original file, such as its creation time, ACLs, and encryption attribute.
The MoveFileEx function also allows an application to specify how to move the file. The function can replace an existing file, move a file across volumes, and delay moving the file until the operating system is restarted.