file.Open(_strDestination, CFile::modeReadWrite | CFile::typeText | CFile::modeCreate | CFile::modeNoTruncate );
CFile::modeNoTruncate Combine this value with modeCreate. If the file being created already exists, it is not truncated to 0 length. Furthermore, if the file being created already exists, the underlying file pointer will point to the beginning of the file. This flag guarantees the file to open, either as a newly created file or as an existing file. This might be useful, for example, when opening a settings file that may or may not exist already. This option applies to CStdioFile as well.