recv() 函数上的 C 段错误 11

Question

我对 C 套接字有疑问。我在 recv(int socket, void *buffer, size_t length, int flags); 函数上出现 Segmentation failure: 11 。我在连接功能中打印了服务器IP。这应该意味着该套接字已正确初始化。

使用函数recv的函数:

int receive_packet(SOCKET *socket, char *packet)
{
    int bytes;
    char data_buffer [2000] = {0};

    bytes = recv(*socket, data_buffer, sizeof(data_buffer), 0);

    if (bytes == 0)
    {
        return 0;
    }

    else if (bytes == SOCKET_ERROR)
    {
        printf("Error: failed to receive packet\n");

        return SOCKET_ERROR;
    }

    else
    {
        memset (packet, 0, bytes);

        strcpy (packet, data_buffer);

        return bytes;
    }
}

主函数在哪里调用函数recv:

int main(int argc, char *argv[])
{
    SOCKET command_socket;
    int port;
    char *host;
    char *username;
    char *password;
    char *packet = NULL;

    host = argv[1];
    port = atoi(argv[2]);
    username = argv[3];
    password = argv[4];

    printf("BEFORE: %d\n", command_socket);

    command_socket = connect_to_server(host, port);

    printf("AFTER: %d\n", command_socket);

    receive_packet(&command_socket, packet);

    printf("Packet: %s\n", packet);

    return 0;
}

输出:

BEFORE: 0
Connected successfully.
AFTER: 3
Segmentation fault: 11

有什么想法吗？!

附注我的基于 UNIX 的操作系统是 OS X。

Answer 1

根据我的理解，SOCKET应该是int类型来表示文件描述符。并且您必须将 NULL 传递给 receive_packet，当取消引用该指针时，您会遇到段故障，这是我能想到为什么您在 recv 中遇到段故障的唯一原因。