(转载)LINUX下c语言SOCKET客户端示范

学习代码，版权归原作者所有。原文：http://www.oschina.net/code/snippet_242622_9944#include <netinet/in.h>    // for sockaddr_in#include <sys/types.h>    // for socket#include <sys/socket.h>    // for socket#include <stdio.h>        // for printf#include <stdlib.h>        // for exit#include <string.h>        // for bzero/* #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> */#define SERVER_PORT 6666#define BUFFER_SIZE 1024#define FILE_NAME_MAX_SIZE 512int main(int argc, char **argv){    if (argc != 2)    {        printf("Please input the IP address of the server \n", argv[0]);        exit(1);    }    //设置一个socket地址结构client_addr,代表客户机internet地址, 端口    struct sockaddr_in client_addr;    bzero(&client_addr, sizeof(client_addr)); //把一段内存区的内容全部设置为0    client_addr.sin_family = AF_INET; //internet协议族    client_addr.sin_addr.s_addr = htons(INADDR_ANY); //INADDR_ANY表示自动获取本机地址    client_addr.sin_port = htons(0); //0表示让系统自动分配一个空闲端口    //创建用于internet的流协议(TCP)socket,用client_socket代表客户机socket    int client_socket = socket(AF_INET, SOCK_STREAM, 0);    if (client_socket < 0)    {        printf("Create Socket Failed!\n");        exit(1);    }    //把客户机的socket和客户机的socket地址结构联系起来    if (bind(client_socket, (struct sockaddr*) &client_addr,            sizeof(client_addr)))    {        printf("Client Bind Port Failed!\n");        exit(1);    }    //设置一个socket地址结构server_addr,代表服务器的internet地址, 端口    struct sockaddr_in server_addr;    bzero(&server_addr, sizeof(server_addr));    server_addr.sin_family = AF_INET;    if (inet_aton(argv[1], &server_addr.sin_addr) == 0) //服务器的IP地址来自程序的参数    {        printf("Server IP Address Error! \n");        exit(1);    }    server_addr.sin_port = htons(SERVER_PORT);    socklen_t server_addr_length = sizeof(server_addr);    // 向服务器发起连接,连接成功后client_socket代表了客户机和服务器的一个socket连接    if (connect(client_socket, (struct sockaddr*) &server_addr,            server_addr_length) < 0)    {        printf("Can Not Connect To %s!\n", argv[1]);        exit(1);    }    // 连接上服务器, 选择要上传的文件    char file_name[FILE_NAME_MAX_SIZE + 1];bzero    (file_name, FILE_NAME_MAX_SIZE + 1);    printf("Please Input File Name Upload To Server: ");    scanf("%s", file_name);    char buffer[BUFFER_SIZE];    bzero(buffer, BUFFER_SIZE);    strncpy(buffer, file_name,            strlen(file_name) > BUFFER_SIZE? BUFFER_SIZE : strlen(file_name));    FILE * fp = fopen(file_name, "r");    if (NULL == fp)    {        printf("File: %s NOT FOUND! \n", file_name);        exit(1);    }    // 发送文件名    int nameLength = send(client_socket, buffer, BUFFER_SIZE, 0);    if (nameLength < 0)    {        printf("File name Error! \n");        exit(0);    }    bzero(buffer, BUFFER_SIZE);    int file_block_length = 0;    while ((file_block_length = fread(buffer, sizeof(char), BUFFER_SIZE, fp))            > 0)    {        if (send(client_socket, buffer, file_block_length, 0) < 0)        {            printf("Send File:\t%s Failed\n", file_name);            break;        }        bzero(buffer, BUFFER_SIZE);    }    printf("File:\t%s Transfer Finished\n", file_name);    fclose(fp);    close(client_socket);    return 0;}