阻塞式socket例子学习

/*************************************************************************
> File Name: Win_Server.c
> Author: SongLee
 ************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <WinSock2.h> 

#define PORT 8087
#define SERVER_IP "127.0.0.1"
#define BUFFER_SIZE 1024
#define FILE_NAME_MAX_SIZE 512
#pragma comment(lib, "WS2_32") 

int main()
{
    // 声明并初始化一个服务端(本地)的地址结构
    sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.S_un.S_addr = INADDR_ANY;
    server_addr.sin_port = htons(PORT); 

    // 初始化socket dll
    WSADATA wsaData;
    WORD socketVersion = MAKEWORD(, );
    if(WSAStartup(socketVersion, &wsaData) != )
    {
        printf("Init socket dll error!");
        exit();
    } 

    // 创建socket
    SOCKET m_Socket = socket(AF_INET, SOCK_STREAM, );
    if (SOCKET_ERROR == m_Socket)
    {
        printf("Create Socket Error!");
        exit();
    } 

    //绑定socket和服务端(本地)地址
    if (SOCKET_ERROR == bind(m_Socket, (LPSOCKADDR)&server_addr, sizeof(server_addr)))
    {
        printf("Server Bind Failed: %d", WSAGetLastError());
        exit();
    } 

    //监听
    if (SOCKET_ERROR == listen(m_Socket, )) //m_Socket监听套接字，专门负责客户端的监听
    {
        printf("Server Listen Failed: %d", WSAGetLastError());
        exit();
    } 

    while()
    {
        printf("Listening To Client...\n"); 

        sockaddr_in client_addr;
        int client_addr_len = sizeof(client_addr); 

        SOCKET m_New_Socket = accept(m_Socket, (sockaddr *)&client_addr, &client_addr_len); //m_New_Socket创建的与客户端通信的socket，后面与客户端通信就依靠这个套接字
        if (SOCKET_ERROR == m_New_Socket)
        {
            printf("Server Accept Failed: %d", WSAGetLastError());
            break;
        } 

        char buffer[BUFFER_SIZE];
        memset(buffer, , BUFFER_SIZE);
        if (recv(m_New_Socket, buffer, BUFFER_SIZE, ) < ) //接收数据是从m_New_Socket
        {
            printf("Server Receive Data Failed!");
            break;
        } 

        char file_name[FILE_NAME_MAX_SIZE+];
        memset(file_name, , FILE_NAME_MAX_SIZE+);
        strncpy(file_name, buffer, strlen(buffer)>FILE_NAME_MAX_SIZE ? FILE_NAME_MAX_SIZE:strlen(buffer));
        printf("%s\n", file_name); 

        FILE * fp = fopen(file_name, "rb"); //windows下是"rb",表示打开一个只读的二进制文件
        if (NULL == fp)
        {
            printf("File: %s Not Found\n", file_name);
        }
        else
        {
            memset(buffer, , BUFFER_SIZE);
            int length = ; 

            while ((length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > )
            {
                if (send(m_New_Socket, buffer, length, ) < )
                {
                    printf("Send File: %s Failed\n", file_name);
                    break;
                }
                memset(buffer, , BUFFER_SIZE);
            } 

            fclose(fp);
            printf("File: %s Transfer Successful!\n", file_name);
        }
        closesocket(m_New_Socket);
    } 

    closesocket(m_Socket);
    //释放winsock库
    WSACleanup();
    return ;
} 

client

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <WinSock2.h> 

#define PORT 8087
#define SERVER_IP "127.0.0.1"
#define BUFFER_SIZE 1024
#define FILE_NAME_MAX_SIZE 512
#pragma comment(lib, "WS2_32")
int main()
{
    //初始化socket dll
    WSADATA wsaData;
    WORD socketVersion = MAKEWORD(, );
    if (WSAStartup(socketVersion, &wsaData) != )
    {
        printf("Init socket dll error!");
        exit();
    }

    //创建socket
    SOCKET c_socket = socket(AF_INET, SOCK_STREAM, );
    if (SOCKET_ERROR == c_socket)
    {
        printf("Create Socket Error!");
        system("pause");
        exit();
    }

    //指定服务器地址
    sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.S_un.S_addr = inet_addr(SERVER_IP);
    server_addr.sin_port = htons(PORT);

    if (SOCKET_ERROR == connect(c_socket, (LPSOCKADDR)&server_addr, sizeof server_addr))//此时系统为c_socket分配一个尚未使用的本地端口
    {
        printf("Can Not Connect To Server IP!\n");
        system("pause");
        exit();
    }

    //输入文件名
    char file_name[FILE_NAME_MAX_SIZE+] = {};
    printf("Please Input File Name On Server: ");
    scanf("%s", &file_name); 

    char buffer[BUFFER_SIZE];
    memset(buffer, , BUFFER_SIZE);
    strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE ? BUFFER_SIZE:strlen(file_name)); 

    //向服务器发送文件名
    if (send(c_socket, buffer, BUFFER_SIZE, ) < )
    {
        printf("Send File Name Failed\n");
        system("pause");
        exit();
    }

    FILE* fp = fopen(file_name, "wb");
    if (NULL == fp)
    {
        printf("File: %s Can Not Open To Write\n", file_name);
        system("pause");
        exit();
    }
    else{
        memset(buffer, , BUFFER_SIZE);
        int length = ;
        while ((length = recv(c_socket, buffer, BUFFER_SIZE, )) > )
        {
            if (fwrite(buffer, sizeof(char), length, fp) < length)
            {
                printf("File: %s Write Failed\n", file_name);
                break;
            }
            memset(buffer, , BUFFER_SIZE);
        }
        printf("Receive File: %s From Server Successful!\n", file_name);
    }
    fclose(fp);
    closesocket(c_socket); 

    //释放winsock库
    WSACleanup(); 

    system("pause");
    return ;
}