Implemented uiParentDestroy() on the Windows and Unix backends. These don't actually *use* it yet; that'll come later. (Ultimately, there should only be one path into window destruction, which leads to one path in uiParent destruction and one path in child destruction.) More TODOs.

TODO.md

@@ -14,6 +14,8 @@
 	- buttons not in tab get drawover issues
 	- buttons in tab without transparent drawing code get copied into the label when stack shown and rehidden
 - see if we can clean up the Darwin backend
+- make the Unix and Windows backend use uiParentDestroy() instead of relying on the autodestroy behavior of the backends
+	- this requires explicitly handling delete events
 
 ultimately:
 - make everything vtable-based

unix/parent.c

@@ -131,6 +131,15 @@ static void uipParent_class_init(uipParentClass *class)
 	GTK_CONTAINER_CLASS(class)->forall = uipParent_forall;
 }
 
+// TODO convert other methods of this + other backends to pp arg p instance variable
+
+static void parentDestroy(uiParent *pp)
+{
+	uipParent *p = uipParent(pp->Internal);
+
+	gtk_widget_destroy(GTK_WIDGET(p));
+}
+
 static uintptr_t parentHandle(uiParent *p)
 {
 	uipParent *pp = uipParent(p->Internal);
@@ -172,6 +181,7 @@ uiParent *uiNewParent(uintptr_t osParent)
 
 	p = uiNew(uiParent);
 	p->Internal = g_object_new(uipParentType, NULL);
+	p->Destroy = parentDestroy;
 	p->Handle = parentHandle;
 	p->SetMainControl = parentSetMainControl;
 	p->SetMargins = parentSetMargins;

windows/parent.c

@@ -211,6 +211,14 @@ const char *initParent(HICON hDefaultIcon, HCURSOR hDefaultCursor)
 	return NULL;
 }
 
+static void parentDestroy(uiParent *pp)
+{
+	struct parent *p = (struct parent *) (pp->Internal);
+
+	if (DestroyWindow(p->hwnd) == 0)
+		logLastError("error destroying uiParent window in parentDestroy()");
+}
+
 static uintptr_t parentHandle(uiParent *p)
 {
 	struct parent *pp = (struct parent *) (p->Internal);
@@ -262,6 +270,8 @@ uiParent *uiNewParent(uintptr_t osParent)
 		(HWND) osParent, NULL, hInstance, p);
 	if (pp->hwnd == NULL)
 		logLastError("error creating uiParent window in uiNewParent()");
+
+	p->Destroy = parentDestroy;
 	p->Handle = parentHandle;
 	p->SetMainControl = parentSetMainControl;
 	p->SetMargins = parentSetMargins;