A CStdioFile object represents a C run-time stream file as opened by the run-time functionfopen. Stream files are buffered and can be opened in either text mode (the default) or binary mode.
是带缓冲的可以是文本, 也可以二进制
Text mode provides special processing for carriage return–linefeed pairs. When you write a newline character (0x0A) to a text-mode CStdioFile object, the byte pair (0x0D, 0x0A) is sent to the file. When you read, the byte pair (0x0A, 0x0D) is translated to a single 0x0A byte.
对回车符号作了特别处理
The CFile functions Duplicate, LockRange, and UnlockRange are not supported for CStdioFile.