如何在Linux中从C执行Python程序 [英] How to execute a Python program from C in Linux

问题描述

我正在使用Raspberry Pi，并且我的C程序完成功能运行后，我需要能够执行python程序.我一直在尝试使用fork和exec，但是，当我使用python3作为exec函数的第一个参数时，我得到的只是控制台中的python命令提示符.

I'm using a Raspberry Pi and I need to be able to execute a python program once my C program finishes running a function. I've been trying to use fork and exec, however, when I use "python3" as the first parameter for the exec function, all I get is the python command prompt in the console.

推荐答案

要回答问题 OP正在使用 execlp 或类似形式，

The OP was using execlp or the like, in the form:

execlp("python3", "name_of_script.py", (char*)0);

(或者，如果他们不知道 NULL 的问题，他们可能已经传递了 NULL 而不是(char *)0 ).

(or if they didn't know about the issue with NULL, they might have passed NULL instead of (char*)0).

问题是， execlp 通常需要传递第一个参数两次;第二次是将其设置为 argv [0] 的值，而几乎总是在 argv [1] 和更高版本中检查用户提供的参数( argv [0] 很少使用，当使用时，主要用于用法/调试输出).当 python3 看到其自己的 argv 时，它会看到它是用 name_of_script.py 的名称"调用的，但没有看到它是一个真正的参数"，因此它就像没有参数启动一样，从而产生了交互式解释器.

Problem is, execlp usually needs the first argument to be passed twice; the second time it's the value to be set as argv[0], while user-supplied arguments are almost always checked for in argv[1] and higher (the value in argv[0] is rarely used, and when it is, it's mostly for usage/debug output). When python3 sees its own argv, it sees that it's been invoked with the "name" of name_of_script.py, but it doesn't see it as a real "argument", so it acts as if it were launched with no arguments, which leads to the interactive interpreter.

解决方法是两次传递程序名称，一次找到程序，一次在 argv 中进行设置，因此参数被 python3 识别为脚本调用:

The fix is to pass the program name twice, once to find the program, once to set it in argv, so the argument is recognized by python3 as a script to invoke:

execlp("python3", "python3", "name_of_script.py", (char*)0);
//        ^ program to find
//                    ^ name to set in argv[0]
//                                  ^ script name to put in argv[1] so script is run

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