Added a framework for handling WM_WININICHANGE to child windows; this will be used by the date-time picker.

redo/windows/events.c

@@ -84,3 +84,41 @@ RUNFN(WM_NOTIFY, notify,
 RUNFN(WM_HSCROLL, hscroll,
 	(HWND) lParam,
 	LOWORD(wParam))
+
+struct wininichange {
+	HWND hwnd;
+	UT_hash_handle hh;
+};
+
+static struct wininichange *wininichanges = NULL;
+
+void uiWindowsRegisterReceiveWM_WININICHANGE(HWND hwnd)
+{
+	struct wininchange *ch;
+
+	HASH_FIND_PTR(wininichanges, &hwnd, ch);
+	if (ch != NULL)
+		complain("window handle %p already subscribed to receive WM_WINICHANGEs in uiWindowsRegisterReceiveWM_WININICHANGE()", hwnd);
+	ch = uiNew(struct wininichange);
+	ch->hwnd = hwnd;
+	HASH_ADD_PTR(wininichanges, hwnd, ch);
+}
+
+void uiWindowsUnregisterReceiveWM_WINICHANGE(HWND hwnd)
+{
+	struct wininichange *ch;
+
+	HASH_FIND_PTR(wininichanges, &hwnd, ch);
+	if (ch == NULL)
+		complain("window handle %p not registered to receive WM_WININICHANGEs in uiWindowsUnregisterReceiveWM_WINICHANGE()", hwnd);
+	HASH_DEL(wininichanges, ch);
+	uiFree(ch);
+}
+
+void issueWM_WININICHANGE(WPARAM wParam, LPARAM lParam)
+{
+	struct wininichange *ch;
+
+	for (ch = wininichanges; ch != NULL; ch = ch->hh.next)
+		SendMessageW(ch->hwnd, WM_WININICHANGE, wParam, lParam);
+}

redo/windows/uipriv_windows.h

@@ -103,6 +103,9 @@ extern void uiWindowsUnregisterWM_HSCROLLHandler(HWND);
 extern BOOL runWM_COMMAND(WPARAM, LPARAM, LRESULT *);
 extern BOOL runWM_NOTIFY(WPARAM, LPARAM, LRESULT *);
 extern BOOL runWM_HSCROLL(WPARAM, LPARAM, LRESULT *);
+extern void uiWindowsRegisterReceiveWM_WININICHANGE(HWND);
+extern void uiWindowsUnregisterReceiveWM_WINICHANGE(HWND);
+extern void issueWM_WININICHANGE(WPARAM, LPARAM);
 
 // dialoghelper.c
 extern void dialogHelperRegisterWindow(HWND);

redo/windows/utilwin.c

@@ -7,6 +7,7 @@
 // - It is the initial parent of all controls. When a control loses its parent, it also becomes that control's parent.
 // - It handles WM_QUERYENDSESSION and console end session requests.
 // - It has a timer to run resizes.
+// - It handles WM_WININICHANGE and forwards the message to any child windows that request it.
 
 #define utilWindowClass L"libui_utilWindowClass"
 
@@ -37,6 +38,9 @@ static LRESULT CALLBACK utilWindowWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, L
 			logLastError("error resetting resize timer in utilWindowWndProc()");
 		doResizes();
 		return 0;
+	case WM_WININICHANGE:
+		issueWM_WININICHANGE(wParam, lParam);
+		return 0;
 	}
 	return DefWindowProcW(hwnd, uMsg, wParam, lParam);
 }