如何在所有前台进程或特定前台进程之前运行后台进程？

Question

这是一个程序system.c

    #include <stdio.h>
    #include <stdlib.h>
    int main()
    {
        system("./client &");
        printf("WE are in main program\n");
        printf("WE are in main program\n");
        printf("WE are in main program\n");
        printf("WE are in main program\n");
        printf("WE are in main program\n");
        return 0;
     }

这是 client.c

#include <stdio.h>
int main()
{
    printf("We are in background process\n");
    do {
        //doing some process on message queue to receive messages
    } while (1);
    return 0;
}   

如何获取输出 ./system 像下面这样从 linux 终端运行

We are in background process
WE are in main program
WE are in main program
WE are in main program
WE are in main program
WE are in main program

谁能更清楚地解释一下？

Answer 1

也许看看这个并激励自己。

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main()
{
    int pid;
    int status;

    pid = fork();
    if (pid == -1)
    {
        // handle error
    }

    if (pid == 0)
    {
        // exec child process
        execl("./client", "client", NULL);
    }
    else
    {
        wait(&status);
    }

    printf("WE are in main program\n");
    printf("WE are in main program\n");
    printf("WE are in main program\n");
    printf("WE are in main program\n");
    printf("WE are in main program\n");
    return 0;
}