Started work on ensuring things get cleaned up. Added a destroy() method to uiControl and implemented most of the work for Windows.

new/control.c

@@ -1,6 +1,11 @@
 // 7 april 2015
 #include "uipriv.h"
 
+void uiControlDestroy(uiControl *c)
+{
+	(*(c->destroy))(c);
+}
+
 uintptr_t uiControlHandle(uiControl *c)
 {
 	return (*(c->handle))(c);

new/newcontrol_windows.c

@@ -15,6 +15,13 @@ struct uiSingleHWNDControl {
 
 #define S(c) ((uiSingleHWNDControl *) (c))
 
+static void singleDestroy(uiControl *c)
+{
+	if (DestroyWindow(S(c)->hwnd) == 0)
+		logLastError("error destroying control in singleDestroy()");
+	// the uiSingleHWNDControl is destroyed in the subclass procedure
+}
+
 static uintptr_t singleHandle(uiControl *c)
 {
 	return (uintptr_t) (S(c)->hwnd);
@@ -57,6 +64,8 @@ static LRESULT CALLBACK singleSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam,
 			return lResult;
 		break;
 	case WM_NCDESTROY:
+		// TODO call an onDestroy handler
+		uiFree(c);
 		if ((*fv_RemoveWindowSubclass)(hwnd, singleSubclassProc, uIdSubclass) == FALSE)
 			logLastError("error removing Windows control subclass in singleSubclassProc()");
 		break;
@@ -79,6 +88,7 @@ uiControl *uiWindowsNewControl(uiWindowsNewControlParams *p)
 	if (c->hwnd == NULL)
 		logLastError("error creating control in uiWindowsNewControl()");
 
+	c->control.destroy = singleDestroy;
 	c->control.handle = singleHandle;
 	c->control.setParent = singleSetParent;
 	c->control.preferredSize = singlePreferredSize;

new/stack.c

@@ -17,6 +17,20 @@ struct stack {
 
 #define S(c) ((stack *) (c))
 
+static void stackDestroy(uiControl *c)
+{
+	stack *s = (stack *) c;
+	uintmax_t i;
+
+	for (i = 0; i < S(c)->len; i++)
+		uiControlDestroy(s->controls[i]);
+	uiFree(s->controls);
+	uiFree(s->stretchy);
+	uiFree(s->width);
+	uiFree(s->height);
+	uiFree(s);
+}
+
 static uintptr_t stackHandle(uiControl *c)
 {
 	return 0;
@@ -163,6 +177,7 @@ uiControl *uiNewHorizontalStack(void)
 
 	s = uiNew(stack);
 
+	s->control.destroy = stackDestroy;
 	s->control.handle = stackHandle;
 	s->control.setParent = stackSetParent;
 	s->control.preferredSize = stackPreferredSize;

new/ui.h

@@ -16,6 +16,9 @@ void uiMain(void);
 void uiQuit(void);
 
 typedef struct uiControl uiControl;
+// TODO public?
+void uiControlDestroy(uiControl *);
+// TODO before destroy?
 uintptr_t uiControlHandle(uiControl *);
 
 typedef struct uiWindow uiWindow;

new/uipriv.h

@@ -12,6 +12,7 @@ struct uiSize {
 
 // TODO handle destruction
 struct uiControl {
+	void (*destroy)(uiControl *);
 	uintptr_t (*handle)(uiControl *);
 	void (*setParent)(uiControl *, uintptr_t);
 	uiSize (*preferredSize)(uiControl *, uiSizing *);

new/window_windows.c

@@ -46,6 +46,8 @@ static LRESULT CALLBACK uiWindowWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPA
 			return 0;
 		break;		// fall through to DefWindowProcW()
 	case WM_DESTROY:
+		if (w->child != NULL)
+			uiControlDestroy(w->child);
 		uiFree(w);
 		break;		// fall through to DefWindowProcW()
 	}