TCPL/7.8.4_Command_Execution

7.8.4 Command Execution 命令执行函数

The function system(char *s) executes the command contained in the character string s, then resumes execution of the current program. The contents of s depend strongly on the local operating system. As a trivial example, on UNIX systems, the statement

   system("date");

causes the program date to be run; it prints the date and time of day on the standard output. system returns a system-dependent integer status from the command executed. In the UNIX system, the status return is the value returned by exit.

函数system(char *s)执行包含在字符串s中的命令，然后继续执行当前程序。s的内容在很大程度上与所用的操作系统有关。下面来看一个UNIX操作系统环境的小例子。语句

   system("date");

将执行程序date，它在标准输出上打印当天的日期和时间。system函数返回一个整型的状态值，其值来自于执行的命令，并同具体系统有关。在UNIX系统中，返回的状态是exit的返回值。