c - 如何为每个子进程分配一个新的终端窗口

Question

我想 fork 多个进程并为每个子进程分配它自己的终端窗口，以便可以轻松演示 IPC。 fork 进行得很好，如果我在同一个终端上运行子进程，它运行良好。然而，为了让每个子进程都有自己的终端窗口，我这样做了

execl("/usr/bin/xterm", "xterm", "-e", "yourprogram", NULL);

程序在新窗口中运行，但其 PID 与 fork 进程的父进程显示的不同。我做错了什么？

谢谢

edit1 - 这是我的主要功能(父进程)。我 fork 了 4 个子进程。我希望每个子进程都有自己的终端窗口。然而，子进程刚刚退出，一个具有不同 PID 的新进程继续在新终端中运行。

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

int main()
{

pid_t pid[4]; 
int i = 0;
int status;

//Fork four new processes
for(i=0; i<4; i++)
{
    pid[i] = fork();

    if(pid[i] == 0 && i == 0)
    {
        execl("/usr/bin/xterm", "xterm", "./child1", NULL);
        exit(1);
    }
    else if(pid[i] == 0 && i == 1)
    {
        execl("/usr/bin/xterm", "xterm", "./child2", NULL);
        exit(1);
    }
    else if(pid[i] == 0 && i == 2)
    {
        execl("/usr/bin/xterm", "xterm", "./child3", NULL);
        exit(1);
    }
    else if(pid[i] == 0 && i == 3)
    {
        execl("/usr/bin/xterm", "xterm", "./child4", NULL);
        exit(1);
    }
    else
    {
        //Parent process
        printf("The main function has forked a process with pid: %d\n", pid[i]);
    }
}

for(i=0;i<4;i++)
{
    status = waitpid(pid[i], NULL, 0);
    if(status == pid[i])
        printf("%d: Process Terminated Successfully\n", pid[i]);
    else
    {
        perror("waitpid");
        exit(1);
    }
}

return 1;
}

edit2 - 添加了 ps -u 输出:

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
dell-pc   3024  0.1  0.0  26872  5480 pts/0    Ss   16:54   0:00 bash
dell-pc   3038  0.0  0.0   4200   632 pts/0    S+   16:54   0:00 ./main
dell-pc   3039 22.5  0.1 109240 11116 pts/0    S+   16:54   0:01 xterm ./child1
dell-pc   3040 26.1  0.1 109240 11268 pts/0    R+   16:54   0:02 xterm ./child2
dell-pc   3041 28.7  0.1 109240 11180 pts/0    S+   16:54   0:02 xterm ./child3
dell-pc   3042 27.0  0.1 109240 11288 pts/0    S+   16:54   0:02 xterm ./child4
dell-pc   3044  4.1  0.0   4200   648 pts/24   Ss+  16:55   0:00 child3
dell-pc   3046  3.7  0.0   4200   680 pts/26   Ss+  16:55   0:00 child4
dell-pc   3048  3.8  0.0   4200   792 pts/25   Ss+  16:55   0:00 child2
dell-pc   3050  3.3  0.0   4200   660 pts/14   Ss+  16:55   0:00 child1
dell-pc   3060  2.0  0.0  26816  5412 pts/27   Ss   16:55   0:00 bash
dell-pc   3072  0.0  0.0  22648  2688 pts/27   R+   16:55   0:00 ps -u

edit3: 添加了 main 的输出:

The main function has forked a process with pid: 3491
The main function has forked a process with pid: 3492
The main function has forked a process with pid: 3493
The main function has forked a process with pid: 3494
3491: Process Terminated Successfully
3492: Process Terminated Successfully
3493: Process Terminated Successfully
3494: Process Terminated Successfully

Answer 1

我做了一个像你的程序(命名为 stackoverflow)，在 xterm 中执行 vi，当它运行时我打开第三个 xterm 来运行 ps -u .输出是:

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
osboxes   1713  0.0  0.2   6588  4756 pts/0    Ss   18:56   0:00 bash
osboxes   1780  0.0  0.2   6508  4484 pts/1    Ss   19:12   0:00 bash
osboxes   1836 88.4  0.0   2020   532 pts/0    R+   19:21   0:29 ./stackoverflow
osboxes   1837  0.1  0.4  12844  8952 pts/0    S+   19:21   0:00 /usr/bin/xterm -e vi stackoverflow.txt
osboxes   1839  0.0  0.1   6072  3536 pts/2    Ss+  19:21   0:00 vi stackoverflow.txt
osboxes   1840  0.0  0.1   4772  2452 pts/1    R+   19:22   0:00 ps -u

程序的输出是:

PID=1836
child PID=1837

因此 child 仍在运行xterm命令。它创建了另一个运行 vi 的子进程(pid 1839)。