Retrieves the size of a file or alternate stream.
qint64 GetFileSize(const QString& qsFileName);
This method retrieves the size, in bytes, of the file or alternate stream specified by FileName. (Note that, for files, the returned value only reflects the size of the file's immediate contents, it does not account for any alternate streams the file may or may not contain.)
The value passed for FileName must be a vault-local absolute path.
Note: This method can only be called when Active is true.
This method returns a Long64 value; after it returns, call the GetLastErrorCode() method to obtain its result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.