I created a window in the child thread and message loop,
When I sent via PostMessage custom message, hope the message loop in the thread exits, but when I received my custom message in the thread and call the DestroyWindow, DestroyWindow blocked and there is no trigger WM_DESTORY, so the message loop threads cannot normal exit,
My question is: what circumstances DestroyWindow blocks? Conflict with other news? Such as MoveWindow? Someone had a similar situation?
The code is as follows:
Destruction of window:

 
# define WM_QUIT_MSG_LOOP (WM_USER + 8600) 
MfxStatus CD3D11Device: : DeleteRenderChildWindow () 
{
The LOG (LS_INFO) & lt; <"Intel D3D11Render, Enter DeleteRenderChildWindow HWND," & lt; 
//SetParent (m_hChildHwnd, NULL); 
If (m_hChildHwnd) {
The LOG (LS_WARNING) & lt; <"Intel D3D11Render DeleteRenderChildWindow, HWND:" & lt; PostMessage (m_hChildHwnd WM_QUIT_MSG_LOOP, NULL, NULL); 
} 

If (m_pChildWindowMsgThread) 
M_pChildWindowMsgThread - & gt; Wait (); 

MSDK_SAFE_DELETE (m_pChildWindowMsgThread); 
MSDK_SAFE_DELETE (m_pCreateFinishEvent); 
The LOG (LS_INFO) & lt; <"Intel D3D11Render, Leave DeleteRenderChildWindow HWND," & lt; 
Return MFX_ERR_NONE; 
} 

Create a window:

 
LRESULT a CALLBACK CD3D11Device: : ChildRenderMsgProc (HWND HWND, UINT uMsg, WPARAM WPARAM, LPARAM LPARAM) {
LRESULT LRESULT=0; 
The switch (uMsg) {
Case WM_DESTROY: {
The LOG (LS_WARNING) & lt; <"Intel D3D11Render ChildRenderMsgProc PostQuitMessage, HWND:" & lt; The PostQuitMessage (0); 
break; 
} 
Case WM_SETCURSOR: {
break; 
} 
Default: 
LResult=DefWindowProc (HWND uMsg, wParam, lParam); 
break; 
} 

Return lResult; 
} 

HWND CD3D11Device: : ThreadCreateChildWindow () {
HMODULE hInstance=nullptr; 
BOOL result=
GetModuleHandleExA (GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | 
GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, 
Reinterpret_cast & lt; Char * & gt; (& amp; DefWindowProc), & amp; HInstance); 

if (! The result) {
The LOG (LS_ERROR) & lt; <"[ThreadCreateChildWindow] GetModuleHandleExA failed."; 
return 0; 
} 

//Register the host window class. See the MSDN documentation of the 
WNDCLASSEXW wcex={}; 
Wcex. CbSize=sizeof (modifed WNDCLASSEX); 
Wcex. LpfnWndProc=& amp; ChildRenderMsgProc; 
Wcex. HInstance=hInstance; 
Wcex. HCursor=LoadCursor (nullptr, IDC_ARROW); 
Wcex. LpszClassName=_T (" Render Window Class "); 
//wcex. Style |=CS_HREDRAW | CS_VREDRAW & amp; ~ WS_CAPTION & amp; ~ WS_SYSMENU; 

//Ignore the error which may happen when the class is already registered. 
RegisterClassExW (& amp; Wcex); 

The RECT rcClient={0}; 
GetWindowRect (m_HandleWindow, & amp; RcClient); 
//Create the host window. 
HWND hChildWindow=
CreateWindowW (_T (" Render Window Class "), _T (" MiniRender "), the WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS, 0, 
0, rcClient. Right - rcClient. RcClient. Bottom - rcClient. Left, top, m_HandleWindow, nullptr, hInstance, nullptr); 
if (! HChildWindow) {
The LOG (LS_ERROR) & lt; <"[ThreadCreateChildWindow] Create the child window failed."; 
return 0; 
} 

ShowWindow (hChildWindow, SW_SHOW); 
SetRenderChildHwnd (hChildWindow); 
M_pCreateFinishEvent - & gt; Signal (); 
The LOG (LS_WARNING) & lt; <"Intel D3D11Render ThreadCreateChildWindow, HWND:" & lt; 
Return hChildWindow; 
} 

Message loop threads:

 
Unsigned int CD3D11Device: : ChildWindowMsgThread (void * CTX) {
CD3D11Device * pD3D11Device=static_cast & lt; CD3D11Device * & gt; (CTX); 

HWND hChildWindow=NULL; 
If (pD3D11Device) {
HChildWindow=pD3D11Device - & gt; ThreadCreateChildWindow (); 
} 

If (hChildWindow==NULL) {
return 0; 
} 

MSG MSG. 
BOOL result; 
While ((result=GetMessage (& amp; MSG, NULL, 0, 0))!=0) {
If (result==1) {
The LOG (LS_ERROR) & lt; <"Intel D3D11Render ChildWindowMsgThread, GetMessage failed, HWND:" & lt; continue; 
} 

If (MSG) message==WM_QUIT_MSG_LOOP) {
The LOG (LS_WARNING) & lt; <"Intel D3D11Render ChildWindowMsgThread, recv WM_QUIT_MSG_LOOP, HWND:" & lt; //DestroyWindow block, according to?? 
The DestroyWindow (hChildWindow); 
} 
The else {
PostMessage (pD3D11Device - & gt; GetParentHwnd (), MSG. Message, MSG. WParam, MSG. LParam); 
} 

The LOG (LS_WARNING) & lt; <"Intel D3D11Render ChildWindowMsgThread, GetMessageing HWND:" & lt; TranslateMessage (& amp; MSG); 
DispatchMessage (& amp; MSG); 
} 

return 0; 
}