(2)shell 返回值:指system所调用的shell命令的返回值,比如上例中,test.sh中返回的值为shell返回值。 2、如何正确判断test.sh是否正确执行? 都错!(仅仅判断status是否==0?或者仅判断status是否!=-1? ) 3、man中对于system的说明 RETURN VALUE The value returned is -1 on error (e.g. fork() failed),...
再来看一下system()函数返回值: The value returned is -1 on error (e.g. fork(2) failed), and the return status of the command otherwise. This latter return status is in the format specified in wait(2). Thus, the exit code of the command will be WEXITSTATUS(status). In case /bin/...
Return value of system by: vashwath | last post by: Hi all, To test the return value of system I wrote 2 programs which are shown below. Program 1: #include <stdio.h> #include <stdlib.h> int main(void) C / C++ 3 4214 Missing return value of a function by: Allerdyce....
1intstatus;2if(NULL == cmdstring)//如果cmdstring为空趁早闪退吧,尽管system()函数也能处理空指针3{4returnXXX;5}6status =system(cmdstring);7if(status <0)8{9printf("cmd: %s\t error: %s", cmdstring, strerror(errno));//这里务必要把errno信息输出或记入Log10returnXXX;11}1213if(WIFEXITED(st...
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对于fork失败,system()函数返回-1。 如果exec执行成功,也即command顺利执行完毕,则返回command通过exit或return返回的值。 (注意,command顺利执行不代表执行成功,比如command:"rm debuglog.txt",不管文件存不存在该command都顺利执行了) 如果exec执行失败,也即command没有顺利执行,比如被信号中断,或者command命令根本...
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C语言中可以使用函数system()、getch()实现按键退出。1、直接调用系统函数 system(“pause”)：system()会调用fork()产生子进程, 由子进程来调用/bin/sh-c string 来执行参数string 字符串所代表的命令, 此命令执行完后随即返回原调用的进程。system(“pause”)可以实现冻结屏幕，便于观察程序的执行...
源代码中，以井号#开头的并不是C语言中的语句。它们属于预处理指令。 在代码被编译前，预处理器会先...
下面列出常用的DOS命令,都可以用system函数调用:ASSOC 显示或修改文件扩展名关联。AT 计划在计算机上运行的命令和程序。ATTRIB 显示或更改文件属性。BREAK 设置或清除扩展式 CTRL+C 检查。CACLS 显示或修改文件的访问控制列表(ACLs)。CALL 从另一个批处理程序调用这一个。CD 显示当前...