digitalmars.D - Access violation after inheriting.
- Zarathustra (131/131) Oct 19 2009 Could somebody explain memory rules in class inheriting?
- Walter Bright (1/1) Oct 19 2009 Try compiling with -gc and run it under the debugger.
- Daniel Keep (13/99) Oct 19 2009 imports are private by default.
Could somebody explain memory rules in class inheriting?
The following code illustrates my problem, look at 'main' function:
//____________________________________________
module window;
private import base;
private import structs;
private static import user32;
private static import kernel32;
private static import gdi32;
private:
extern (Windows) dword wndProc(ptr o_hwnd, dword o_msg, dword o_wparam, dword
o_lparam){
alias user32.EWindowMessage WM;
auto l_wnd = cast(Window*)user32.getWindowLong(o_hwnd, 0x00);
if(o_msg == WM.NCCREATE){
user32.setWindowLong(o_hwnd, 0x00, *(cast(dword*)o_lparam));
}
else if(l_wnd is null){
return 0x00;
}
return (cast(Window*)user32.getWindowLong(o_hwnd, 0x00)).wndProc(o_hwnd,
o_msg, o_wparam, o_lparam);
}
public:
class Window{
private const ptr handle;
void onMouseDown (MouseEventArgs o_mea){
}
this(){
WINWndClassEx wndClass;
wndClass.size = 0x00000030;
wndClass.style = 0x00000003;
wndClass.wndProc = cast(ptr)&.wndProc;
wndClass.clsExtraBytes = 0x00000000;
wndClass.wndExtraBytes = 0x00000004;
wndClass.hInstance = kernel32.getModuleHandle(null);
wndClass.hIcon = user32.loadIcon(null, 0x00007F00);
wndClass.hCursor = user32.loadCursor(null, 0x00007F00);
wndClass.hbrBackground = gdi32.getStockObject(0x00000000);
wndClass.menuName = null;
wndClass.className = cast(wstr)"clsname";
wndClass.hIconSm = user32.loadIcon(null, 0x00007F00);
if(!user32.registerClassEx(cast(ptr)&wndClass)){
if(kernel32.getLastError() != 0x0582){
user32.messageBox(null,
user32.translateErrorCode(kernel32.getLastError()), cast(wstr)"error",
0x00000000);
assert(false, "window class registering failed");
}
}
handle = user32.createWindowEx(
0,
wndClass.className,
cast(wstr)"<applicationcaption>",
0x00CF0000,
0x00000000,
0x00000000,
0x00000280,
0x000001E0,
null,
null,
kernel32.getModuleHandle(null),
cast(ptr)&this
);
if(handle is null){
user32.messageBox(null,
user32.translateErrorCode(kernel32.getLastError()), cast(wstr)"error",
0x00000000);
assert(false, "window creating failed");
}
}
public void run(){
WINMsg msg;
user32.showWindow(handle, 0x0000000A);
user32.updateWindow(handle);
while(user32.getMessage(cast(ptr)&msg, null, 0, 0)){
user32.translateMessage(cast(ptr)&msg);
user32.dispatchMessage(cast(ptr)&msg);
}
}
private dword wndProc(ptr o_hwnd, dword o_msg, dword o_wparam, dword
o_lparam){
alias user32.EWindowMessage WM;
alias user32.EMouseKey WK;
switch(o_msg){
case WM.DESTROY:
user32.postQuitMessage(0x00);
break;
case WM.LBUTTONDOWN:
MouseEventArgs l_mea;
l_mea.button = MouseButton.LEFT;
l_mea.location.x = loword(o_lparam);
l_mea.location.x = hiword(o_lparam);
onMouseDown(l_mea);
break;
case WM.RBUTTONDOWN:
MouseEventArgs l_mea;
l_mea.button = MouseButton.RIGHT;
l_mea.location.x = loword(o_lparam);
l_mea.location.x = hiword(o_lparam);
onMouseDown(l_mea);
break;
default: return user32.defWindowProc(o_hwnd, o_msg, o_wparam, o_lparam);
}
return 0;
}
}
//____________________________________________
module main:
// ...
class MyWindow : Window{
this(){
super();
}
override void onMouseDown(MouseEventArgs o_mea){
MsgBox(cast(char[])"Hello");
}
}
void main(){
try{
Window wnd = new Window();
MyWindow mywnd = new MyWindow();
wnd .run(); // ok
mywnd.run(); // access violation onClick
}
catch(Object o){
MsgBox(cast(char[])o.toString);
}
}
//____________________________________________
Oct 19 2009
Walter Bright <newshound1 digitalmars.com> Try compiling with -gc and run it under the debugger.
Oct 19 2009
Zarathustra wrote:Could somebody explain memory rules in class inheriting? The following code illustrates my problem, look at 'main' function:Posts like this belong on d.learn.//____________________________________________ module window; private import base; private import structs; private static import user32; private static import kernel32; private static import gdi32;imports are private by default.private: extern (Windows) dword wndProc(ptr o_hwnd, dword o_msg, dword o_wparam, dword o_lparam){ alias user32.EWindowMessage WM; auto l_wnd = cast(Window*)user32.getWindowLong(o_hwnd, 0x00); if(o_msg == WM.NCCREATE){ user32.setWindowLong(o_hwnd, 0x00, *(cast(dword*)o_lparam)); } else if(l_wnd is null){ return 0x00; } return (cast(Window*)user32.getWindowLong(o_hwnd, 0x00)).wndProc(o_hwnd, o_msg, o_wparam, o_lparam); }You shouldn't be using Window*: see below.public: class Window{ private const ptr handle; void onMouseDown (MouseEventArgs o_mea){ } this(){ WINWndClassEx wndClass; wndClass.size = 0x00000030; wndClass.style = 0x00000003; wndClass.wndProc = cast(ptr)&.wndProc;What is ptr? If it's void*, you don't need to do this. Incidentally, there's already a set of bindings for the Win32 api. Not sure where the current version is; somewhere on dsource.org.wndClass.clsExtraBytes = 0x00000000; wndClass.wndExtraBytes = 0x00000004; wndClass.hInstance = kernel32.getModuleHandle(null); wndClass.hIcon = user32.loadIcon(null, 0x00007F00); wndClass.hCursor = user32.loadCursor(null, 0x00007F00); wndClass.hbrBackground = gdi32.getStockObject(0x00000000); wndClass.menuName = null; wndClass.className = cast(wstr)"clsname";Easier to type "clsname"w than cast(wstr)"clsname"wndClass.hIconSm = user32.loadIcon(null, 0x00007F00); ... handle = user32.createWindowEx( 0, wndClass.className, cast(wstr)"<applicationcaption>", 0x00CF0000, 0x00000000, 0x00000000, 0x00000280, 0x000001E0, null, null, kernel32.getModuleHandle(null), cast(ptr)&this );this is a reference to the object. &this is the address at which the reference is being stored, which is probably *on the stack*. I wouldn't be surprised if this is why it's segfaulting.if(handle is null){ user32.messageBox(null, user32.translateErrorCode(kernel32.getLastError()), cast(wstr)"error", 0x00000000); assert(false, "window creating failed"); } } ... class MyWindow : Window{ this(){ super(); } override void onMouseDown(MouseEventArgs o_mea){ MsgBox(cast(char[])"Hello");Unless MsgBox is defined very strangely, the cast(char[]) here should be superfluous.} } ...
Oct 19 2009