用API函数实现串行通讯,以往的DOS系统是通过DOS中断和BIOS中断向用户提供串行接口的通讯能力。在Windows环境下，C++的开发工具既没有提供象DOS和BIOS中那样专门的串行通讯控制方法，也不允许用户直接控制串口的中断。-API function used to achieve serial communication, in the past, the DOS system is through the DOS interrupt and BIOS interrupt serial interface to provide users with communications capabilities. In the Windows environment, C++ Development tools did not provide as DOS and BIOS as specialized in serial communication control method, but also does not allow users to directly control the serial port interrupts.