Linux IPC 进程之间通信——无名管道实例

Linux IPC 进程之间通信——无名管道实例

无名管道只限于有亲缘关系的父子进程之间进行同行

#include  
#include 
#include 
#include  
#include  
#include  
#include 


int main() 
{ 
    int pipe_fd[2];
    pid_t pid;
    char buf_r[100];
    int r_num;
    memset(buf_r,0,sizeof(buf_r));


    
    if(pipe(pipe_fd)<0)
    {
        printf("pipe create errorn");
        return -1;
    }
	printf("-----fd[0]=%d-----fd[1]=%d----n", pipe_fd[0], pipe_fd[1]);
    
    if((pid=fork())==0)
    {
        printf("n");
        
        close(pipe_fd[1]);
        sleep(2);
        
        if((r_num=read(pipe_fd[0],buf_r,100))>0){
            printf("%d  numbers  read  from  the  pipe  is  %sn",r_num,buf_r);
        }
        
        close(pipe_fd[0]);
        exit(0);
    }
    else if(pid>0)
    {
        
        close(pipe_fd[0]);
        if(write(pipe_fd[1],"Hello",5)!= -1)
            printf("parent write1 success!n");
        if(write(pipe_fd[1]," Pipe",5)!= -1)
            printf("parent write2 success!n");
        
        close(pipe_fd[1]);
        sleep(3);
        
        waitpid(pid,NULL,0);
        exit(0);
    }
    
    return 0;
} 

运行效果：

-----fd[0]=3-----fd[1]=4----
parent write1 success!
parent write2 success!

10  numbers  read  from  the  pipe  is  Hello Pipe

其它控制

流向

进程名

fd[0]

fd[1]

父写子读

父进程

close

write

子进程

read

close

子写父读

父进程

read

close

子进程

close

write

与有名管道之间差异

亲缘关系

非亲缘关系

pipe（无名管道）

√

×

named pipe（有名管道）

√

√