比execlp(cmd [0]，cmd [0]，cmd [1]，cmd [2]，cmd [3] NULL)更有效的方法； [英] A more efficient way than: execlp(cmd[0], cmd[0], cmd[1] cmd[2], cmd[3] NULL);

问题描述

我正在尝试制作一个命令行Iinterface程序，该程序可以从用户输入中获取代码行并使用execlp执行它们.

i am trying to make a Command Line Iinterface program that can get line of code from user input and execute them using execlp.

我想知道是否有更好的方式编写代码.

I wanna know if there is a better way of writing my code.

execlp(cmd[0], cmd[0], cmd[1] cmd[2], cmd[3] NULL);
perror("Execlp");

例如，用户输入4个单词，每个单词将存储在:

For example user enter 4 words and each of them will be store in:

cmd[0] cmd[1] cmd[2] cmd[3]

如果我们使用cc helloworld.c -o helloworld的编译功能 这将在数​​组cmd[]

if we use compile function which is cc helloworld.c -o helloworld this will require 4 space inside array cmd[]

或者我们使用./helloworld

它将存储在cmd[0]中并运行它，这很好用

it will be store in cmd[0] and run it, great this works

但是我假设如果有一个功能需要四个以上的单词，我的程序将能够执行它们吗?答案可能是否"，例如:如果有5个或更多的单词，我不认为我的程序能够运行它，除非在我的函数中它将有5个元素起作用

but i assume what if there is a function which require more than 4 words, will my program be able to execute them? Answer is probably no, E.g.: if theres is 5 or more words , i dont think my program will be able to run it unless in my function it will have 5 element to work

execlp(cmd[0], cmd[0], cmd[1] cmd[2], cmd[3]. cmd[4], NULL);

或

execlp(cmd[0], cmd[0], cmd[1] cmd[2], cmd[3], cmd[4], cmd[5], cmd[6], NULL);
perror("Execlp");

是否有更有效的方法来做到这一点?通过使用exec()系列中的其他功能.

Is there a more efficient way to do this? by using other function within exec() family.

谢谢:)

推荐答案

使用execvp()怎么办?例如:

[STEP 110] # cat execvp.c
#include <unistd.h>

int
main(int argc, char *argv[])
{
    /* argv[argc] is always NULL */
    execvp(argv[1], &argv[1]);
    return 0;
}
[STEP 111] # gcc -Wall execvp.c
[STEP 112] # ./a.out echo 1
1
[STEP 113] # ./a.out echo 1 2
1 2
[STEP 114] # ./a.out echo 1 2 3
1 2 3
[STEP 115] #

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