socketpair与管道pipe

在看Android 输入系统的时候，第一次看到socketpair，发现和管道非常相似。唯他们的区别就是socketpair，默认支持全双工，而pipe是半双工的。他们一样只能用在父子进程或者线程之间通信。

下面分别以socketpair和管道实现全双工通信。

管道实现线程间全双工通信

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

#define SIZE 1024

int fd1[2],fd2[2]; //fd1[0]:read,  fd1[1]:write

void *func_thread1(void *arg)
{
char buf[SIZE] = {0};
int cnt = 0;
while(1)
{
sprintf(buf,"hello main  %d\n",cnt++);
write(fd1[1],buf,strlen(buf));
int len = read(fd2[0],buf,SIZE);
buf[len] = '\0';
printf("%s",buf);
bzero(buf,SIZE);
sleep(3);
}
return NULL;
}

int main(int agrc,char**argv)
{
pthread_t thread1_t;

/*1. create pipe*/
pipe(fd1);
pipe(fd2);
/*2. create thread1*/
pthread_create(&thread1_t, NULL,
func_thread1, NULL);
char buf[SIZE] = {0};
int cnt = 0;
char * p = buf;
printf("buf[SIZE] sizeof:%d,  strlen:%d\n",sizeof(buf),strlen(buf));
printf(" char * p  sizeof:%d,  strlen:%d\n",sizeof(p),strlen(p));
while(1){
int len = read(fd1[0],buf,SIZE);
buf[len] = '\0';
printf("%s",buf);
bzero(buf,SIZE);
sprintf(buf,"hello thread  %d\n",cnt++);
write(fd2[1],buf,strlen(buf));
sleep(3);
}
return 0;
}

Socketpair实现线程间全双工通信

#include <stdio.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>

#define SIZE 1024

void *func_thread1(void *arg)
{
char buf[SIZE] = {0};
int cnt = 0;
int fd = (int)arg;
while(1)
{
sprintf(buf,"hello main  %d\n",cnt++);
write(fd,buf,strlen(buf));
int len = read(fd,buf,SIZE);
buf[len] = '\0';
printf("%s",buf);
bzero(buf,SIZE);
sleep(3);
}
return NULL;
}

int main(int agrc,char**argv)
{
int fd[2];
pthread_t thread1_t;

/*1. create socketpair*/
int ret = socketpair(AF_UNIX,SOCK_STREAM,0,fd);
if(ret < 0){
perror("socketpair");
exit(-1);
}
/*2. create thread1*/
pthread_create(&thread1_t, NULL,
func_thread1, fd[1]);
char buf[SIZE] = {0};
int cnt = 0;
char * p = buf;

while(1){
int len = read(fd[0],buf,SIZE);
buf[len] = '\0';
printf("%s",buf);
bzero(buf,SIZE);
sprintf(buf,"hello thread  %d\n",cnt++);
write(fd[0],buf,strlen(buf));
sleep(3);
}
return 0;
}