一个简单的socket编程实例

备忘：

## client.c
~~~~~~~~~~~~~~~~~
#include
#include
#include
#include
#include
#include
#include

#define BUF_LEN  1024
#define SERVER_PORT  6789

int main(int argc, char* argv[])
{
    int    sockfd = 0;
    char   recvline[BUF_LEN] = {0};
    char   sendline[BUF_LEN] = {0};
    struct sockaddr_in    servaddr;
    memset(&servaddr, 0x00, sizeof(struct sockaddr_in));

    /* check parameter */
    if(argc != 2){
        printf("usage: ./client \n");
        exit(0);
    }

    /* create socket */
    if( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ){
        printf("create socket error! errno = %d\n", errno);
        exit(0);
    }

    /* init server address */
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(SERVER_PORT);
    if( inet_pton(AF_INET, argv[1], &servaddr.sin_addr) == -1){
        printf("inet_pton error for %s\n",argv[1]);
        exit(0);
    }

    if( connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1){
        printf("connect error: %s(errno: %d)\n",strerror(errno),errno);
        exit(0);
    }

    printf("send msg to server: \n");
    /* send message to server*/
    fgets(sendline, BUF_LEN, stdin);
    if( send(sockfd, sendline, strlen(sendline), 0) == -1)
    {
        printf("send msg error: %s(errno: %d)\n", strerror(errno), errno);
        exit(0);
    }

    close(sockfd);
    exit(0);
}


server.c
~~~~~~~~~~~~~~~~~~~~~
#include
#include
#include
#include
#include
#include
#include

#define BUF_LEN  1024
#define SERVER_PORT  6789

int main(int argc, char* argv[])
{
    int    sockfd = 0;
    int    connfd = 0;
    int     recv_len = 0;
    char    buff[BUF_LEN] = {0};
    struct sockaddr_in     servaddr;
    memset(&servaddr, 0x00, sizeof(struct sockaddr_in));

    /* create server's socket */
    if( (sockfd= socket(AF_INET, SOCK_STREAM, 0)) == -1 ){
        printf("create socket error: %s(errno: %d)\n",strerror(errno),errno);
        exit(0);
    }

    /* init server socket struct */
    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(SERVER_PORT);

    if( bind(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1){
        printf("bind socket error: %s(errno: %d)\n",strerror(errno),errno);
        exit(0);
    }

    if( listen(sockfd, 5) == -1){
        printf("listen socket error: %s(errno: %d)\n",strerror(errno),errno);
        exit(0);
    }

    printf("## SERVER START\n");
    while(1)
    {
        /* recv client's date */
        if( (connfd = accept(sockfd, (struct sockaddr*)NULL, NULL)) == -1)
        {
            printf("accept socket error: %s(errno: %d)",strerror(errno),errno);
            continue;
        }
        recv_len = recv(connfd, buff, BUF_LEN, 0);
        buff[recv_len] = '\0';
        printf("recv msg from client: %s\n", buff);
        close(connfd);
    }

    close(sockfd);
}