linux进程控制开发实例

最新推荐文章于 2021-12-26 12:24:42 发布

转载最新推荐文章于 2021-12-26 12:24:42 发布 · 131 阅读

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#嵌入式

本文通过三个C语言示例程序，详细介绍了Linux环境下进程控制的核心概念和技术，包括创建子进程(fork)、执行新程序(exec)及等待子进程结束(waitpid)等关键操作。

fork.c

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

int main(void)
{
    pid_t result;
    
    result = fork();
    
    if (result == -1)
    {
        printf("Fork Error!\n");
    }
    else
    {
        if (result == 0)
        {
            printf("The returned value is %d\nThe child process!!\nMy PID is %d\n", result, getpid());
        }
        else
        {
            printf("The returned value is %d\nThe father process!!\nMy PID is %d\n", result, getpid());
        }
    }
    
    return 0;
}

exec.c

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

int main(void)
{
    pid_t result;
    
    result = fork();
    
    if (result == 0)
    {
        if (execlp("ps", "ps", "-ef", NULL) < 0)
        {
            printf("Execlp error\n");
        }
    }
    
    return 0;
}

waitpid.c

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

int main(void)
{
    pid_t pc, pr;
    
    pc = fork();
    
    if (pc < 0)
    {
        printf("Error fork\n");
    }
    else if (pc == 0)
    {
        sleep(5);
        exit(0);
    }
    else
    {
        do
        {
            pr = waitpid(pc, NULL, WNOHANG);
            
            if(pr == 0)
            {
                printf("The child process has not exited!\n");
                sleep(1);
            }
        }while (pr == 0);
        
        if (pr == pc)
        {
            printf("Get child exit code: %d\n", pr);
        }
        else
        {
            printf("Some error occured.\n");
        }
    }
    
    return 0;
}