c语言socket之非阻塞模型开发服务器与客户端。

非阻塞方式，你懂的

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


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

    int fd = socket(AF_INET, SOCK_STREAM, 0);
    if(fd < 0){
        printf("create socket failed!, errno=%d\n",errno);
    }
    struct sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = htonl(INADDR_ANY);
    addr.sin_port = htons(8008);

    int ret;
    ret = bind(fd, (struct sockaddr*) &addr, sizeof(addr));
    if(ret == -1){
        printf("bind failed!, errno=%d",errno);
        close(fd);
    }
    ret = listen(fd, SOMAXCONN);
    if(ret == -1){
        printf("listen failed!, errno=%d",errno);
    }
    struct sockaddr_in clientaddr;
    socklen_t clientaddrlen = sizeof(clientaddr);
    int afd = accept(fd, (struct sockaddr*) &clientaddr, &clientaddrlen);
    if(afd != -1){
        printf("A client connected!,ip=%s,port=%d\n",inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port));
        char buf[256] = {0};
        sleep(5);
        ret = recv(afd, buf, 256, 0);
        if(ret > 0){
            printf("recv %d byte:%s\n",ret,buf);
        }
        else if(ret == -1){
            printf("recv error!,errno=%d\n",errno);
        }
        else{
            printf("client disconnect!\n");
        }
    }
    else{
        printf("accept failed!,errno=%d\n",errno);
    }
}

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

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


    if(argc != 3){
        printf("please input IP port\n");
    }
    char* ip = argv[1];
    unsigned int port = atoi(argv[2]);
    int fd = socket(AF_INET, SOCK_STREAM, 0);
    if(fd < 0){
        printf("create socket failed!, errno=%d\n",errno);
    }
    struct sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = inet_addr(ip);
    addr.sin_port = htons(port);

    int ret;
    ret = connect(fd, (struct sockaddr*) &addr, sizeof(addr));
    if(ret == -1){
        printf("connect failed!, errno=%d",errno);
    }
    else{
        //连接成功后将fd设置为非阻塞
        int flags = fcntl(fd, F_GETFL);
        flags |= O_NONBLOCK;
        ret = fcntl(fd, F_SETFL, flags);
        if(ret == -1){
            printf("set O_NONBLOCK failed!,errno=%d\n",errno);
        }
        char *buf = "hello, I am a client!";
        int cnt = 0;
        while(1){
            ret = send(fd, buf, strlen(buf), 0);
            if(ret > 0){
                cnt++;
                printf("send %d byte:%s,cnt = %d\n",ret,buf,cnt);
            }
            else if(ret == -1){
                if(errno == EAGAIN){
                    printf("send try again\n");
                    sleep(1);
                    continue;
                }
                else
                    printf("send error!,errno=%d\n",errno);
            }
            else{
                printf("server disconnect!\n");
            }
        }

    }

}