Android中socketpair双向通信详解

#include <pthread.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>  /* See NOTES */
#include <sys/socket.h>
#define SOCKET_BUFFER_SIZE (32768U)


/* 参考:
 * frameworks\native\libs\input\InputTransport.cpp
 */

/* 线程1函数实现 */
 void *function_thread1 (void *arg)
 {
 int fd = (int)arg;/* 把文件句柄转换出来 */
 char buf[500];
 int len;
 int cnt = 0;

 while (1)
 {
 /* 向 main线程发出: Hello, main thread */
 len = sprintf(buf, "Hello, main thread, cnt = %d", cnt++);
 write(fd, buf, len);

 /* 读取数据(main线程发回的数据) */
 len = read(fd, buf, 500);
 buf[len] = '\0';
 printf("%s\n", buf);

 /* 延时5秒钟 */
 sleep(5);
 }

 return NULL;
 }



 int main(int argc, char **argv)
 {
 int sockets[2];

 /* 使用 socketpair 得到两个文件句柄到数组sockets */
 socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets);

 /* 设置缓冲区, 每个文件句柄对应两个缓冲区，两个文件对应四个 */
 int bufferSize = SOCKET_BUFFER_SIZE;
 setsockopt(sockets[0], SOL_SOCKET, SO_SNDBUF, &bufferSize, sizeof(bufferSize));
 setsockopt(sockets[0], SOL_SOCKET, SO_RCVBUF, &bufferSize, sizeof(bufferSize));
 setsockopt(sockets[1], SOL_SOCKET, SO_SNDBUF, &bufferSize, sizeof(bufferSize));
 setsockopt(sockets[1], SOL_SOCKET, SO_RCVBUF, &bufferSize, sizeof(bufferSize));

 /* 创建线程1(thread1),并把文件句柄sockets[1]传给子线程thread1 */
 pthread_t threadID;
 pthread_create(&threadID, NULL, function_thread1, (void *)sockets[1]);

 char buf[500];
 int len;
 int cnt = 0;
 int fd = sockets[0];/* 当前main函数的文件句柄是sockets[0] */


 while(1)
 {
 /* 读数据: 读线程1发出的数据 */
 len = read(fd, buf, 500);
 buf[len] = '\0';
 printf("%s\n", buf);

 /* main thread向thread1 发出: Hello, thread1 */
 len = sprintf(buf, "Hello, thread1, cnt = %d", cnt++);
 write(fd, buf, len);
 }
 }