请问CSocket的Attach,Detach有什么作用，在什么场合下用比较合适，急．．．．

Question

谢谢!

Answer 1

CAsyncSocket与SOCKE之间是通过一个线程局部存储的Map来实现映射关系的。
Attach就是向这个局部存储的Map添加一项，Deatch就是从这个Map删除其自己。

Answer 2

void PASCAL CAsyncSocket::AttachHandle(
SOCKET hSocket, CAsyncSocket* pSocket, BOOL bDead)
{
_AFX_SOCK_THREAD_STATE* pState = _afxSockThreadState; BOOL bEnable = AfxEnableMemoryTracking(FALSE);
if (!bDead)
{
ASSERT(CAsyncSocket::LookupHandle(hSocket, bDead) == NULL);
if (pState->m_pmapSocketHandle->IsEmpty())
{
ASSERT(pState->m_pmapDeadSockets->IsEmpty());
ASSERT(pState->m_hSocketWindow == NULL); CSocketWnd* pWnd = new CSocketWnd;
pWnd->m_hWnd = NULL;
if (!pWnd->CreateEx(0, AfxRegisterWndClass(0),
_T("Socket Notification Sink"),
WS_OVERLAPPED, 0, 0, 0, 0, NULL, NULL))
{
TRACE(traceSocket, 0, "Warning: unable to create socket notify window!\n");
AfxThrowResourceException();
}
ASSERT(pWnd->m_hWnd != NULL);
ASSERT(CWnd::FromHandlePermanent(pWnd->m_hWnd) == pWnd);
pState->m_hSocketWindow = pWnd->m_hWnd;
}
pState->m_pmapSocketHandle->SetAt((void*)hSocket, pSocket);
}
else
{
void* pvCount;
INT_PTR nCount;
if (pState->m_pmapDeadSockets->Lookup((void*)hSocket, pvCount))
{
nCount = (INT_PTR)pvCount;
nCount++;
}
else
nCount = 1;
pState->m_pmapDeadSockets->SetAt((void*)hSocket, (void*)nCount);
}
AfxEnableMemoryTracking(bEnable);
}void PASCAL CAsyncSocket::DetachHandle(SOCKET hSocket, BOOL bDead)
{
ASSERT(CAsyncSocket::LookupHandle(hSocket, bDead) != NULL); _AFX_SOCK_THREAD_STATE* pState = _afxSockThreadState;
if (!bDead)
{
pState->m_pmapSocketHandle->RemoveKey((void*)hSocket);
if (pState->m_pmapSocketHandle->IsEmpty())
{
ASSERT(pState->m_hSocketWindow != NULL);
CWnd* pWnd =
CWnd::FromHandlePermanent(pState->m_hSocketWindow);
ASSERT_VALID(pWnd); if (pWnd != NULL)
{
pWnd->DestroyWindow();
delete pWnd;
} pState->m_hSocketWindow = NULL; pState->m_pmapDeadSockets->RemoveAll(); while (!pState->m_plistSocketNotifications->IsEmpty())
delete pState->m_plistSocketNotifications->RemoveHead();
}
}
else
{
void* pvCount;
INT_PTR nCount;
if (pState->m_pmapDeadSockets->Lookup((void*)hSocket, pvCount))
{
nCount = (INT_PTR)pvCount;
nCount--;
if (nCount == 0)
pState->m_pmapDeadSockets->RemoveKey((void*)hSocket);
else
pState->m_pmapDeadSockets->SetAt((void*)hSocket, (void*)nCount);
}
}
}楼主看了这些MFC的源码就明白了。

Answer 3

Attach将CSocket绑定到一个Socket句柄
Detach反之，返回一个句柄
我一般用它们将CSocket绑定到一个API打开的Socket句柄，或者在多线程中线程之间传递socket连接

Answer 4

通俗的理解：Detach 和 Attach就像接力棒(SOCKET句柄就是接力棒)的两个人

Answer 5

Attach
就是将一个句柄绑定一个对象上。

Answer 6

MFCSocs.exe Avoids Two Common MFC Socket Mistakeshttp://support.microsoft.com/default.aspx?scid=kb;EN-US;185728