#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

void error_handling(char *message);

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

    int serv_sock;
    int clnt_sock;
    struct sockaddr_in serv_addr;
    struct sockaddr_in clnt_addr;
    socklen_t clnt_addr_size;

    char message[] = "hello word!";

    if (argc != 2) {
        printf("usage: %s<port>\n", argv[0]);
        exit(1);
    }
    //调用socket函数创建套接字
    serv_sock =  socket(PF_INET, SOCK_STREAM, 0);
    if (serv_sock == -1) {
        error_handling("socket() error");
    }

	//清空 并绑定数据
    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_addr.sin_port = htons(atoi(argv[1]));

	//绑定地址信息 ip地址 端口号
    if (bind(serv_sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1) {
        error_handling("bind() error");
    }

	//进入监听状态
    if (listen(serv_sock, 5) == -1) {
        error_handling("listen() error");
    }

    clnt_addr_size = sizeof(clnt_addr_size);
	//当有请求到来时，接收请求
    clnt_sock = accept(serv_sock, (struct sockaddr*)&clnt_addr, &clnt_addr_size);
    if(clnt_sock == -1)
        error_handling("accept error");

    write(clnt_sock, message, sizeof(message));
    printf("关闭");
    close(clnt_sock);
    close(serv_sock);

    return 0;
}

void error_handling(char *message) {
    fputs(message, stderr);
    fputc('\n', stderr);
    exit(1);
}