如何在C / C ++上在Linux操作系统上启动进程 [英] How to start process on Linux OS in C, C++

问题描述

我有无线USB适配器，我使用pstree命令来监视所有进程。

当我插入USB适配器到我的Linux操作系统时，我看到新的进程wpa_supplicant与pstree命令。

我使用C / C ++语言。我知道Linux操作系统将使用NetworkManager守护程序来监控网络（eth，蓝牙，wifi等），但我不知道如何我们可以启动wpa_supplicant？我可以使用dbus或systemd吗？

感谢
Thong LT

解决方案>

使用fork（）系统调用，它将创建一个子进程或者如果你想通过C代码运行可执行文件，然后使用exec（）库函数并指定可执行文件的路径。

这里是代码：

 ＃include< unistd.h> 
＃include< stdio.h> 
＃include< sys / types.h> 
＃include< stdlib.h> 
＃include< sys / wait.h> 
 
 int main（）{
 pid_t pid，p; 
 int i，status; 
 printf（Parent process starting with PID =％d it's Parent ID％d\\\
，（int）getpid（），（int）getppid（））; 
 
 if（（pid = fork（））==  -  1）{
 fprintf（stderr，FORK FAILED\\\
）; 
 return -1; 
} 
 if（pid == 0）{
 printf（Child process starting with PID =％d\\\
，（int）getpid（））; 
 for（i = 0; i <5; i ++）{
 printf（Child prints [％d] \\\
，i）; 
 sleep（2）; 
} 
 _exit（0）; 
 // exit（0）; 
} 
 else {
 p = wait（& status）; 
 printf（父继续执行，从子进程控制％d \\\
，（int）p）; 
 // printf（孩子的返回状态是％d \\\
，status）; 
 for（i = 0; i <5; i ++）{
 sleep（2）; 
 printf（Parent prints [％d] \\\
，i）; 
 // sleep（2）; 
} 
 _exit（0）; 
} 
 return 0; 
  

}

I have wireless USB Adapter and I use "pstree" command to monitor all processes.
When I plug the USB adapter into my Linux OS I see new process "wpa_supplicant" with "pstree" command.

I use in C/C++ language . I know Linux OS will use "NetworkManager" daemon to monitor network (eth, bluetooth, wifi. etc) but i don't know How to we can start "wpa_supplicant" ? Can i use dbus or systemd?

Thanks Thong LT

解决方案

Use fork() system call and it will create a child process or if you want to run the executable through C code then use exec() library function and specify the path of the executable.

Here is the code:

#include<unistd.h>
#include<stdio.h>
#include<sys/types.h>
#include<stdlib.h>
#include<sys/wait.h>

int main() {
pid_t pid,p;
int i,status;
printf("Parent process starts with PID = %d it's Parent ID %d\n",(int)getpid(),(int)getppid());

if((pid = fork())==-1) {
    fprintf(stderr,"FORK FAILED\n");
    return -1;
}
if(pid == 0 ) {
    printf("Child process starts with PID = %d\n",(int)getpid());
    for(i = 0 ; i < 5; i++) {
        printf("Child prints [%d]\n",i);
        sleep(2);
    }
    _exit(0);
    //exit(0);
}
else {
    p  = wait(&status);
    printf("Parent resumes execution, took control from the child %d \n",(int)p);
    //printf("Return status of the child is %d\n",status);
    for(i = 0; i< 5 ; i++) {
        sleep(2);
        printf("Parent prints [%d]\n",i);
        //sleep(2);
    }
    _exit(0);
}
return 0;

}

这篇关于如何在C / C ++上在Linux操作系统上启动进程的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！