程序从标准输入读入数据输出至指定输出文件，并根据输入的要求同步写或异步写。

此程序的主体在于read和write函数的配合使用以实现将从输入文件读入的数据复制到输出文件。-procedures from the standard input output read data to the designated output file, and in accordance with the requirements of the importation of synchronous or asynchronous write write. This procedure is the main read and write functions to achieve with the use of input from the document read into the data Minute system to the output document.