其中ConnectEx界定？

问题描述

我想在Windows7的使用ConnectEx功能，具有MSVC2010。

I want to use ConnectEx function on Windows7, with MSVC2010.

我收到错误C3861：'ConnectEx'：标识符找不到

I am getting error C3861: 'ConnectEx': identifier not found

MSDN暗示的作用应该mswsock.h声明，然而，检​​查的话，它是没有定义。

MSDN suggests the function should be declared in mswsock.h, however, when checking it, it's not defined there.

任何提示？

推荐答案

如果你还读入的你提到的，它说：

If you read further into the MSDN article for ConnectEx() you mentioned, it says:

注意作为 ConnectEx 必须获得函数的函数指针
  在通过向功能
   SIO_GET_EXTENSION_FUNCTION_POINTER 运code指定。输入缓冲器
  传递给函数的WSAIoctl必须包含 WSAID_CONNECTEX ，一
  全局唯一标识符（GUID）值标识的 ConnectEx
  扩展功能。如果成功，由的WSAIoctl 返回的输出
  函数包含一个指向 ConnectEx 功能。该
   WSAID_CONNECTEX GUID中定义的 Mswsock.h 的头文件。

不像其他的Windows API函数， ConnectEx（）必须在运行时加载，因为头文件实际上并不包含函数声明ConnectEx（）（它确实有一个的typedef 用于调用的函数 LPFN_CONNECTEX ）和文档没有明确提及您必须链接到为了这个工作（这通常是其他Windows API函数的情况下）特定库。

Unlike other Windows API functions, ConnectEx() must be loaded at runtime, as the header file doesn't actually contain a function declaration for ConnectEx() (it does have a typedef for the function called LPFN_CONNECTEX) and the documentation doesn't specifically mention a specific library that you must link to in order for this to work (which is usually the case for other Windows API functions).

下面是一个如何得到这个工作（错误检查省略博览会）的例子：

Here's an example of how one could get this to work (error-checking omitted for exposition):

#include <Winsock2.h> // Must be included before Mswsock.h
#include <Mswsock.h>

// Required if you haven't specified this library for the linker yet
#pragma comment(lib, "Ws2_32.lib")

/* ... */

SOCKET s = /* ... */;
DWORD numBytes = 0;
GUID guid = WSAID_CONNECTEX;
LPFN_CONNECTEX ConnectExPtr = NULL;
int success = ::WSAIoctl(s, SIO_GET_EXTENSION_FUNCTION_POINTER,
    (void*)&guid, sizeof(guid), (void*)&ConnectExPtr, sizeof(ConnectExPtr),
    &numBytes, NULL, NULL);
// Check WSAGetLastError()!

/* ... */

// Assuming the pointer isn't NULL, you can call it with the correct parameters.
ConnectExPtr(s, name, namelen, lpSendBuffer,
    dwSendDataLength, lpdwBytesSent, lpOverlapped);

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