C语言 linux环境基于socket的简易即时通信程序 Prime

转载请注明出处：http://www.cnblogs.com/kevince/p/3891033.html      ——By Kevince

最近在看linux网络编程相关，现学现卖，就写了一个简易的C/S即时通信程序，代码如下：

head.h

/*头文件，client和server编译时都需要使用*/
#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <pthread.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define MSGLEN 1000
#define IPLEN 15

typedef int SOCKET;

server.c:

/*server*/

#include "head.h"

char msg_recv[MSGLEN], msg_send[MSGLEN];
SOCKET server_sockfd, client_sockfd;

void *thread_function(void *argv) /*线程函数*/
{
    while(1){
        gets(msg_send);
        write(client_sockfd, msg_send, MSGLEN);
    }
    pthread_exit(NULL);
}

int main(int arg, char *argv[])
{
    int server_len, client_len;
    struct sockaddr_in server_address;
    struct sockaddr_in client_address;
    int port;
    int res;

    pthread_t a_thread;
    void *thread_result;

    if (arg != 2){
        printf("server --portnum\n");
        exit(EXIT_FAILURE);
    }

    sscanf(argv[1], "%d", &port); /*读入端口*/

    server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = inet_addr("127.0.0.1");
    server_address.sin_port = htons(port);

    server_len = sizeof(server_address);
    bind(server_sockfd, (struct sockaddr *)&server_address, server_len); /*绑定端口并监听*/
    listen(server_sockfd, 10);
    printf("listen...\n");

    client_len = sizeof(client_address);
    client_sockfd = accept(server_sockfd, (struct sockaddr *)&client_address, &client_len);
    printf("connection success!\n");

    res = pthread_create(&a_thread, NULL, thread_function, NULL); /*启动线程函数*/
    if (res != 0){
        perror("Thread creation failed");
        exit(EXIT_FAILURE);
    }

    while(read(client_sockfd, msg_recv, MSGLEN)){
        printf("msg from client: %s\n", msg_recv);
    }
    close(client_sockfd);
    exit(EXIT_SUCCESS);
}

client.c:

/*client*/

#include "head.h"

char msg_recv[MSGLEN],msg_send[MSGLEN];
SOCKET sockfd;

void *thread_function(void *argv) /*线程函数*/
{
    while(1){
        gets(msg_send);
        write(sockfd, msg_send, MSGLEN);
    }
    pthread_exit(NULL);
}

int main(int arg, char *argv[])
{
    struct sockaddr_in address;
    int len;
    int res;
    int port;
    char ip[IPLEN];

    void *thread_result;
    pthread_t a_thread;

    sockfd = socket(AF_INET, SOCK_STREAM, 0);

    if (arg != 3){
        printf("client --ipaddress --portnum\n");
        exit(EXIT_FAILURE);
    }

    sscanf(argv[1], "%s", ip);
    sscanf(argv[2], "%d", &port); /*读取ip与端口*/

    address.sin_family = AF_INET;
    address.sin_addr.s_addr = inet_addr(ip);
    address.sin_port = htons(port);

    len = sizeof(address);
    res = connect(sockfd, (struct sockaddr *)&address, len);
    if (res == -1){
        perror("connect failed! ");
        exit(EXIT_FAILURE);
    }
    printf("connection success!\n");

    res = pthread_create(&a_thread, NULL, thread_function, NULL); /*启动线程函数*/
    if (res != 0){
        perror("Thread creation failed");
        exit(EXIT_FAILURE);
    }

    while(read(sockfd, msg_recv, MSGLEN)){
        printf("msg from server: %s\n", msg_recv);
    }
    res = pthread_join(a_thread, &thread_result);
    if (res != 0){
        perror("joined failed");
        exit(EXIT_FAILURE);
    }
    exit(EXIT_SUCCESS);
}

由于使用了线程，所以要链接正确的线程库，所以编译命令如下：

gcc -D_REENTRANT -I/usr/include/nptl server.c -o server -L/usr/lib/nptl -lpthread

gcc -D_REENTRANT -I/usr/include/nptl client.c -o client -L/usr/lib/nptl -lpthread

如果你的系统默认使用的就是NPTL线程库，那么编译时就无需加上-I和-L选项

运行时输入的命令规则是：

./server --portnum  #即server后面要加上需要绑定的端口号。

./client --ip --portnum  #即client后面要加上服务器的IP地址以及端口号。

不积跬步无以至千里，虽然这两个程序很简单，但作为我的第一个linux环境下基于socket的通信程序，也很有纪念意义。