socket之recv() 阻塞&非阻塞

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我不是萧海哇 2022-09-16 06:51:23 博主文章分类：C/C++ ©著作权

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server.c
 
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
 
#define MYPORT 8100 //连接时使用的端口
#define MAXCLINE 5 //连接队列中的个数
int conn_amount; //当前的连接数
 
 
int main(void)
{
    int sock_fd,new_fd; //监听套接字 连接套接字
    struct sockaddr_in server_addr; // 服务器的地址信息
    struct sockaddr_in client_addr; //客户端的地址信息
    socklen_t sin_size;
    int yes = 1;
    char buf[1024];
    int ret;
    int i;
 
    //建立sock_fd套接字
    if((sock_fd = socket(AF_INET,SOCK_STREAM,0))==-1)
    {
        perror("setsockopt");
        exit(1);
    }
    printf("sockect_fd = %d\n", sock_fd);
 
    server_addr.sin_family = AF_INET; //主机字节序
    server_addr.sin_port = htons(MYPORT);
    server_addr.sin_addr.s_addr = INADDR_ANY;//通配IP
    memset(server_addr.sin_zero,'\0',sizeof(server_addr.sin_zero));
 
    if(bind(sock_fd,(struct sockaddr *)&server_addr,sizeof(server_addr)) == -1)
    {
        perror("bind error!\n");
        exit(1);
    }
    if(listen(sock_fd,MAXCLINE)==-1)
    {
        perror("listen error!\n");
        exit(1);
    }
    printf("listen port %d\n",MYPORT);
    new_fd = accept(sock_fd,(struct sockaddr *)NULL, NULL);
    if(new_fd == -1){
        printf("accept socket error: %s\n",strerror(errno));
    }
    int count = 0;
int flag = 0;
//MSG_DONTROUTE 绕过路由表查找。
//MSG_DONTWAIT 仅本操作非阻塞。
//MSG_OOB 发送或接收带外数据。
//MSG_PEEK 窥看外来消息。
//MSG_WAITALL 等待所有数据。
    while(1)
    {
        printf("第 %d 次recv \n",++count);
        ret = recv(new_fd,buf,sizeof(buf),flag);
        if(ret > 0){
            printf("收到 %d Byte[%s] \n",ret,buf);
        }else if (ret < 0){
            if(ret == EAGAIN){
                printf("没有数据可读\n");
            }
        }else{
            printf("连接断开\n");
            break;
        }
        sleep(1);
 
    }
}

client.c
//客户端
#include <sys/types.h> 
#include <sys/socket.h> 
#include <stdio.h> 
#include <netinet/in.h> 
#include <arpa/inet.h> 
#include <unistd.h> 
#include <stdlib.h>
#include <sys/time.h>
#include <string.h>
#define SERVER_IP "192.192.255.63"
int main() 
{ 
    int client_sockfd; 
    int len; 
    struct sockaddr_in address;//服务器端网络地址结构体 
    int result; 
    int count = 0;
    char msg[16];
    client_sockfd = socket(AF_INET, SOCK_STREAM, 0);//建立客户端socket 
    address.sin_family = AF_INET; 
    //address.sin_addr.s_addr = inet_addr(SERVER_IP);
    address.sin_addr.s_addr =INADDR_ANY; 
    address.sin_port = htons(8100); 
    len = sizeof(address); 
    result = connect(client_sockfd, (struct sockaddr *)&address, len); 
    if(result == -1) 
    { 
        perror("oops: client2"); 
        exit(1); 
    } 
    int flag = 0;
    while(1){
        memset(msg,0,sizeof(msg));
        sprintf(msg,"client-> send%d",count++);
        send(client_sockfd, msg, sizeof(msg),flag); 
        printf("client have send %s \n",msg);
        sleep(15);
    }
    close(client_sockfd); 
 
    return 0; 
}