socket以C语音实现linux和windows文件传输

在C语言中实现文件传输可以使用socket编程来完成。下面是一个简单的例子，演示如何在Linux和Windows系统之间传输文件。

首先，我们需要在服务器端创建一个socket，然后监听客户端的连接请求。当有客户端连接时，我们可以接收客户端发送的文件，并将其保存到本地。

服务器端代码如下：

// server.c

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

#define PORT 8080

int main(int argc, char const *argv[]) {
    int server_fd, new_socket, valread;
    struct sockaddr_in address;
    int opt = 1;
    int addrlen = sizeof(address);
    char buffer[1024] = {0};

    // create socket file descriptor
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("socket failed");
        exit(EXIT_FAILURE);
    }

    // set socket options
    if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT,
                   &opt, sizeof(opt))) {
        perror("setsockopt failed");
        exit(EXIT_FAILURE);
    }

    // bind socket to port
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);

    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }

    // listen for incoming connections
    if (listen(server_fd, 3) < 0) {
        perror("listen failed");
        exit(EXIT_FAILURE);
    }

    printf("Waiting for connections...\n");

    // accept incoming connection
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t *)&addrlen)) < 0) {
        perror("accept failed");
        exit(EXIT_FAILURE);
    }

    printf("Connection established\n");

    // receive file from client
    FILE *fp;
    fp = fopen("output.txt", "w");
    while ((valread = read(new_socket, buffer, 1024)) > 0) {
        fwrite(buffer, sizeof(char), valread, fp);
    }
    fclose(fp);

    printf("File received and saved as output.txt\n");

    // close socket
    close(new_socket);
    close(server_fd);

    return 0;
}

接下来是客户端代码，我们需要创建一个socket并连接到服务器，然后将本地文件发送给服务器。

// client.c

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

#define PORT 8080

int main(int argc, char const *argv[]) {
    int sock = 0, valread;
    struct sockaddr_in serv_addr;
    char buffer[1024] = {0};

    // create socket file descriptor
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        printf("\n Socket creation error \n");
        return -1;
    }

    // set server address and port
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(PORT);

    // convert IPv4 and IPv6 addresses from text to binary form
    if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
        printf("\nInvalid address/ Address not supported \n");
        return -1;
    }

    // connect to server
    if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
        printf("\nConnection Failed \n");
        return -1;
    }

    printf("Connected to server\n");

    // send file to server
    FILE *fp;
    fp = fopen("input.txt", "r");
    while (!feof(fp)) {
        int n = fread(buffer, sizeof(char), 1024, fp);
        send(sock, buffer, n, 0);
    }
    fclose(fp);

    printf("File sent\n");

    // close socket
    close(sock);

    return 0;
}

这两个程序可以在Linux和Windows系统上编译和运行。为了在Windows上编译，您需要使用Winsock库，例如使用MinGW环境。