c++ - 套接字始终返回INVALID_SOCKET

我正在尝试为学校项目创建多线程服务器，并且我依赖于我过去编写的类似代码，但是由于某种原因，在open函数中，该代码始终进入if语句并崩溃。
是什么阻止了它创建套接字？

#pragma comment(lib, "Ws2_32.lib")
#include <WinSock2.h>
#include <exception>
#include <iostream>
#include <string>
#include <numeric>
#include <deque>
#include <queue>
#include <mutex>
#include <condition_variable>

void accept();
void open();
void close();
void bindAndListen();

#ifdef _DEBUG
#include <stdio.h>
#define TRACE(msg, ...) printf(msg "\n", __VA_ARGS__);

#else
#define TRACE(msg, ...) printf(msg "\n", __VA_ARGS__);
#define TRACE(msg, ...)
#endif

static const unsigned short PORT = 8826;
static const unsigned int IFACE = 0;
SOCKET _socket;

void clientHandler(SOCKET client_socket);
void close();
int main()
{
    open();
}

void bindAndListen()
{
    struct sockaddr_in sa = { 0 };
    sa.sin_port = htons(PORT);
    sa.sin_family = AF_INET;
    sa.sin_addr.s_addr = IFACE;

    if (bind(_socket, (struct sockaddr*) & sa, sizeof(sa)) == SOCKET_ERROR)
        throw std::exception(__FUNCTION__ " - bind");
    TRACE("binded");

    if (listen(_socket, SOMAXCONN) == SOCKET_ERROR)
        throw std::exception(__FUNCTION__ " - listen");
    TRACE("listening...");
}

void clientHandler(SOCKET client_socket)
{
    std::cout << "hello";
}

void close()
{
    TRACE(__FUNCTION__ " closing accepting socket");
    try
    {
        closesocket(_socket);
    }
    catch (...) {}
}
void open()
{
    _socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (_socket == INVALID_SOCKET)
        throw std::exception(__FUNCTION__ " - socket");
}

void accept()
{
    SOCKET client_socket = accept(_socket, NULL, NULL);
    if (client_socket == INVALID_SOCKET)
        throw std::exception(__FUNCTION__);

    TRACE("Client accepted !");
    // create new thread for client and detach from it
    std::thread tr(&clientHandler, _socket);
    tr.detach();
}

最佳答案

您应该调用WSAGetLastError来获取导致返回INVALID_SOCKET的实际错误代码。

在这种情况下，您似乎没有调用WSAStartup，因此收到了WSANOTINITIALISED错误。

使用任何Winsock函数之前，必须先调用WSAStartup。