socketpair

与pipe的区别

pipe产生的文件描述符是半双工的,需要pipe两次才能实现全双工,产生的两个描述符是一个读,一个写
socketpair直接就可以全双工,产生的两个文件描述符的任何一个都可读可写

pipe例子

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
 
int main(){
    int fd1[2],fd2[2];
 
    if(pipe(fd1) < 0 || pipe(fd2) < 0)
        exit(-1);
 
    if(fork()){
        int val=0;
        close(fd1[0]);
        close(fd2[1]);
 
        while(1){
            sleep(1);
            ++val;
            printf("parent send: %d
",val);
            write(fd1[1],&val,sizeof(val));
            read(fd2[0],&val,sizeof(val));
            printf("parent received: %d
",val);
        }
    }else{
        int val;
        close(fd1[1]);
        close(fd2[0]);
 
        while(1){
            read(fd1[0],&val,sizeof(val));
            printf("son Data received: %d
",val);
            ++val;
            write(fd2[1],&val,sizeof(val));
            printf("son send: %d
",val);
        }
    }
}

socketpair例子

#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
 
int main(){
    int fd[2];
    int ret;
 
    ret=socketpair(AF_LOCAL,SOCK_STREAM,0,fd);
    if(ret < 0){
        perror("socketpair");
        exit(-1);
    }
 
    if(fork()){
        int val=0;
        close(fd[1]);
        while(1){
            sleep(1);
            ++val;
            printf("parent sending data: %d
",val);
            write(fd[0],&val,sizeof(val));
            read(fd[0],&val,sizeof(val));
            printf("parent Data received: %d
",val);
        }
    }else{
        int val;
        close(fd[0]);
        while(1){
            read(fd[1],&val,sizeof(val));
            printf("son Data received: %d
",val);
            ++val;
            write(fd[1],&val,sizeof(val));
            printf("son send received: %d
",val);
        }
    }
}