diff --git a/const_windows.go b/const_windows.go
index cba0578..86f58df 100644
--- a/const_windows.go
+++ b/const_windows.go
@@ -39,28 +39,6 @@ const (
 
 	_SC_CLOSE = 0xf060
 
-	_WM_DESTROY     = 0x0002
-	_WM_CLOSE       = 0x0010
-	_WM_SETFONT     = 0x0030
-	_WM_SETICON     = 0x0080
-	_WM_NCCREATE    = 0x0081
-	_WM_NCDESTROY   = 0x0082
-	_WM_COMMAND     = 0x0111
-	_WM_SYSCOMMAND  = 0x0112
-	_WM_DPICHANGED  = 0x02e0
-	_WM_USER        = 0x0400
-	_EM_SETSEL      = 0x00b1
-	_LB_ADDSTRING   = 0x0180
-	_LB_GETCURSEL   = 0x0188
-	_LB_GETSELCOUNT = 0x0190
-	_LB_GETSELITEMS = 0x0191
-	_MCM_GETCURSEL  = 0x1001
-	_MCM_SETCURSEL  = 0x1002
-	_PBM_SETPOS     = _WM_USER + 2
-	_PBM_SETRANGE32 = _WM_USER + 6
-	_PBM_SETMARQUEE = _WM_USER + 10
-	_STM_SETICON    = 0x0170
-
 	_GWL_STYLE = -16
 
 	_PROGRESS_CLASS = "msctls_progress32"
diff --git a/date_windows.go b/date_windows.go
index 043f19f..f70f5c8 100644
--- a/date_windows.go
+++ b/date_windows.go
@@ -97,7 +97,7 @@ func (dlg *calendarDialog) setup(text string, opts options) (time.Time, error) {
 		date.year = uint16(year)
 		date.month = uint16(month)
 		date.day = uint16(day)
-		sendMessage.Call(dlg.dateCtl, _MCM_SETCURSEL, 0, uintptr(unsafe.Pointer(&date)))
+		sendMessage.Call(dlg.dateCtl, win.MCM_SETCURSEL, 0, uintptr(unsafe.Pointer(&date)))
 	}
 
 	dlg.layout(getDPI(dlg.wnd))
@@ -111,7 +111,7 @@ func (dlg *calendarDialog) setup(text string, opts options) (time.Time, error) {
 		go func() {
 			select {
 			case <-opts.ctx.Done():
-				sendMessage.Call(dlg.wnd, _WM_SYSCOMMAND, _SC_CLOSE, 0)
+				sendMessage.Call(dlg.wnd, win.WM_SYSCOMMAND, _SC_CLOSE, 0)
 			case <-wait:
 			}
 		}()
@@ -128,11 +128,11 @@ func (dlg *calendarDialog) setup(text string, opts options) (time.Time, error) {
 
 func (dlg *calendarDialog) layout(dpi dpi) {
 	font := dlg.font.forDPI(dpi)
-	sendMessage.Call(dlg.textCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.dateCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.okBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.cancelBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.extraBtn, _WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.textCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.dateCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.okBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.cancelBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.extraBtn, win.WM_SETFONT, font, 1)
 	setWindowPos.Call(dlg.wnd, 0, 0, 0, dpi.scale(281), dpi.scale(281), _SWP_NOZORDER|_SWP_NOMOVE)
 	setWindowPos.Call(dlg.textCtl, 0, dpi.scale(12), dpi.scale(10), dpi.scale(241), dpi.scale(16), _SWP_NOZORDER)
 	setWindowPos.Call(dlg.dateCtl, 0, dpi.scale(12), dpi.scale(30), dpi.scale(241), dpi.scale(164), _SWP_NOZORDER)
@@ -149,30 +149,30 @@ func (dlg *calendarDialog) layout(dpi dpi) {
 func calendarProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointer) uintptr {
 	var dlg *calendarDialog
 	switch msg {
-	case _WM_NCCREATE:
+	case win.WM_NCCREATE:
 		saveBackRef(wnd, *lparam)
 		dlg = (*calendarDialog)(*lparam)
-	case _WM_NCDESTROY:
+	case win.WM_NCDESTROY:
 		deleteBackRef(wnd)
 	default:
 		dlg = (*calendarDialog)(loadBackRef(wnd))
 	}
 
 	switch msg {
-	case _WM_DESTROY:
+	case win.WM_DESTROY:
 		postQuitMessage.Call(0)
 
-	case _WM_CLOSE:
+	case win.WM_CLOSE:
 		dlg.err = ErrCanceled
 		destroyWindow.Call(wnd)
 
-	case _WM_COMMAND:
+	case win.WM_COMMAND:
 		switch wparam {
 		default:
 			return 1
 		case win.IDOK, win.IDYES:
 			var date _SYSTEMTIME
-			sendMessage.Call(dlg.dateCtl, _MCM_GETCURSEL, 0, uintptr(unsafe.Pointer(&date)))
+			sendMessage.Call(dlg.dateCtl, win.MCM_GETCURSEL, 0, uintptr(unsafe.Pointer(&date)))
 			dlg.out = time.Date(int(date.year), time.Month(date.month), int(date.day), 0, 0, 0, 0, time.UTC)
 		case win.IDCANCEL:
 			dlg.err = ErrCanceled
@@ -181,7 +181,7 @@ func calendarProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointe
 		}
 		destroyWindow.Call(wnd)
 
-	case _WM_DPICHANGED:
+	case win.WM_DPICHANGED:
 		dlg.layout(dpi(uint32(wparam) >> 16))
 
 	default:
diff --git a/entry_windows.go b/entry_windows.go
index 6d09cb1..13af8f6 100644
--- a/entry_windows.go
+++ b/entry_windows.go
@@ -97,7 +97,7 @@ func (dlg *entryDialog) setup(text string, opts options) (string, error) {
 	centerWindow(dlg.wnd)
 	setFocus.Call(dlg.editCtl)
 	showWindow.Call(dlg.wnd, _SW_NORMAL, 0)
-	sendMessage.Call(dlg.editCtl, _EM_SETSEL, 0, intptr(-1))
+	sendMessage.Call(dlg.editCtl, win.EM_SETSEL, 0, intptr(-1))
 
 	if opts.ctx != nil {
 		wait := make(chan struct{})
@@ -105,7 +105,7 @@ func (dlg *entryDialog) setup(text string, opts options) (string, error) {
 		go func() {
 			select {
 			case <-opts.ctx.Done():
-				sendMessage.Call(dlg.wnd, _WM_SYSCOMMAND, _SC_CLOSE, 0)
+				sendMessage.Call(dlg.wnd, win.WM_SYSCOMMAND, _SC_CLOSE, 0)
 			case <-wait:
 			}
 		}()
@@ -122,11 +122,11 @@ func (dlg *entryDialog) setup(text string, opts options) (string, error) {
 
 func (dlg *entryDialog) layout(dpi dpi) {
 	font := dlg.font.forDPI(dpi)
-	sendMessage.Call(dlg.textCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.editCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.okBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.cancelBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.extraBtn, _WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.textCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.editCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.okBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.cancelBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.extraBtn, win.WM_SETFONT, font, 1)
 	setWindowPos.Call(dlg.wnd, 0, 0, 0, dpi.scale(281), dpi.scale(141), _SWP_NOZORDER|_SWP_NOMOVE)
 	setWindowPos.Call(dlg.textCtl, 0, dpi.scale(12), dpi.scale(10), dpi.scale(241), dpi.scale(16), _SWP_NOZORDER)
 	setWindowPos.Call(dlg.editCtl, 0, dpi.scale(12), dpi.scale(30), dpi.scale(241), dpi.scale(24), _SWP_NOZORDER)
@@ -143,24 +143,24 @@ func (dlg *entryDialog) layout(dpi dpi) {
 func entryProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointer) uintptr {
 	var dlg *entryDialog
 	switch msg {
-	case _WM_NCCREATE:
+	case win.WM_NCCREATE:
 		saveBackRef(wnd, *lparam)
 		dlg = (*entryDialog)(*lparam)
-	case _WM_NCDESTROY:
+	case win.WM_NCDESTROY:
 		deleteBackRef(wnd)
 	default:
 		dlg = (*entryDialog)(loadBackRef(wnd))
 	}
 
 	switch msg {
-	case _WM_DESTROY:
+	case win.WM_DESTROY:
 		postQuitMessage.Call(0)
 
-	case _WM_CLOSE:
+	case win.WM_CLOSE:
 		dlg.err = ErrCanceled
 		destroyWindow.Call(wnd)
 
-	case _WM_COMMAND:
+	case win.WM_COMMAND:
 		switch wparam {
 		default:
 			return 1
@@ -173,7 +173,7 @@ func entryProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointer)
 		}
 		destroyWindow.Call(wnd)
 
-	case _WM_DPICHANGED:
+	case win.WM_DPICHANGED:
 		dlg.layout(dpi(uint32(wparam) >> 16))
 
 	default:
diff --git a/file_windows.go b/file_windows.go
index d9e7918..939e8db 100644
--- a/file_windows.go
+++ b/file_windows.go
@@ -348,9 +348,9 @@ func browseForFolder(opts options) (string, []string, error) {
 	return str, []string{str}, nil
 }
 
-func browseForFolderCallback(wnd uintptr, msg uint32, lparam, data uintptr) uintptr {
+func browseForFolderCallback(wnd win.HWND, msg uint32, lparam, data uintptr) uintptr {
 	if msg == 1 { // BFFM_INITIALIZED
-		sendMessage.Call(wnd, 1024+103 /* BFFM_SETSELECTIONW */, 1 /* TRUE */, data)
+		win.SendMessage(wnd, 1024+103 /* BFFM_SETSELECTIONW */, 1 /* TRUE */, data)
 	}
 	return 0
 }
diff --git a/internal/win/user32.go b/internal/win/user32.go
index 6d1e16b..a7b0534 100644
--- a/internal/win/user32.go
+++ b/internal/win/user32.go
@@ -27,6 +27,28 @@ const (
 	MB_DEFBUTTON1        = windows.MB_DEFBUTTON1
 	MB_DEFBUTTON2        = windows.MB_DEFBUTTON2
 	MB_DEFBUTTON3        = windows.MB_DEFBUTTON3
+
+	WM_DESTROY     = 0x0002
+	WM_CLOSE       = 0x0010
+	WM_SETFONT     = 0x0030
+	WM_SETICON     = 0x0080
+	WM_NCCREATE    = 0x0081
+	WM_NCDESTROY   = 0x0082
+	WM_COMMAND     = 0x0111
+	WM_SYSCOMMAND  = 0x0112
+	WM_DPICHANGED  = 0x02e0
+	WM_USER        = 0x0400
+	EM_SETSEL      = 0x00b1
+	LB_ADDSTRING   = 0x0180
+	LB_GETCURSEL   = 0x0188
+	LB_GETSELCOUNT = 0x0190
+	LB_GETSELITEMS = 0x0191
+	MCM_GETCURSEL  = 0x1001
+	MCM_SETCURSEL  = 0x1002
+	PBM_SETPOS     = WM_USER + 2
+	PBM_SETRANGE32 = WM_USER + 6
+	PBM_SETMARQUEE = WM_USER + 10
+	STM_SETICON    = 0x0170
 )
 
 func MessageBox(hwnd HWND, text *uint16, caption *uint16, boxtype uint32) (ret int32, err error) {
@@ -34,3 +56,7 @@ func MessageBox(hwnd HWND, text *uint16, caption *uint16, boxtype uint32) (ret i
 }
 
 //sys GetDlgCtrlID(wnd HWND) (ret int) = user32.GetDlgCtrlID
+//sys SendMessage(wnd HWND, msg uint32, wparam uintptr, lparam uintptr) (ret uintptr) = user32.SendMessageW
+//sys SetWindowText(wnd HWND, text *uint16) (err error) = user32.SetWindowTextW
+//sys EnumChildWindows(parent HWND, enumFunc uintptr, lparam uintptr) = user32.EnumChildWindows
+//sys EnumWindows(enumFunc uintptr, lparam uintptr) (err error) = user32.EnumChildWindows
diff --git a/internal/win/zsyscall_windows.go b/internal/win/zsyscall_windows.go
index 10a1c85..130d932 100644
--- a/internal/win/zsyscall_windows.go
+++ b/internal/win/zsyscall_windows.go
@@ -62,7 +62,10 @@ var (
 	procSHCreateItemFromParsingName = modshell32.NewProc("SHCreateItemFromParsingName")
 	procSHGetPathFromIDListEx       = modshell32.NewProc("SHGetPathFromIDListEx")
 	procShell_NotifyIconW           = modshell32.NewProc("Shell_NotifyIconW")
+	procEnumChildWindows            = moduser32.NewProc("EnumChildWindows")
 	procGetDlgCtrlID                = moduser32.NewProc("GetDlgCtrlID")
+	procSendMessageW                = moduser32.NewProc("SendMessageW")
+	procSetWindowTextW              = moduser32.NewProc("SetWindowTextW")
 	procWTSSendMessageW             = modwtsapi32.NewProc("WTSSendMessageW")
 )
 
@@ -161,12 +164,39 @@ func ShellNotifyIcon(message uint32, data *NOTIFYICONDATA) (ret int, err error)
 	return
 }
 
+func EnumChildWindows(parent HWND, enumFunc uintptr, lparam uintptr) {
+	syscall.Syscall(procEnumChildWindows.Addr(), 3, uintptr(parent), uintptr(enumFunc), uintptr(lparam))
+	return
+}
+
+func EnumWindows(enumFunc uintptr, lparam uintptr) (err error) {
+	r1, _, e1 := syscall.Syscall(procEnumChildWindows.Addr(), 2, uintptr(enumFunc), uintptr(lparam), 0)
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func GetDlgCtrlID(wnd HWND) (ret int) {
 	r0, _, _ := syscall.Syscall(procGetDlgCtrlID.Addr(), 1, uintptr(wnd), 0, 0)
 	ret = int(r0)
 	return
 }
 
+func SendMessage(wnd HWND, msg uint32, wparam uintptr, lparam uintptr) (ret uintptr) {
+	r0, _, _ := syscall.Syscall6(procSendMessageW.Addr(), 4, uintptr(wnd), uintptr(msg), uintptr(wparam), uintptr(lparam), 0, 0)
+	ret = uintptr(r0)
+	return
+}
+
+func SetWindowText(wnd HWND, text *uint16) (err error) {
+	r1, _, e1 := syscall.Syscall(procSetWindowTextW.Addr(), 2, uintptr(wnd), uintptr(unsafe.Pointer(text)), 0)
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func WTSSendMessage(server Handle, sessionID uint32, title *uint16, titleLength int, message *uint16, messageLength int, style uint32, timeout int, response *uint32, wait bool) (err error) {
 	var _p0 uint32
 	if wait {
diff --git a/list_windows.go b/list_windows.go
index 93a1d25..e5c5b36 100644
--- a/list_windows.go
+++ b/list_windows.go
@@ -111,7 +111,7 @@ func (dlg *listDialog) setup(text string, opts options) ([]string, error) {
 	}
 
 	for _, item := range dlg.items {
-		sendMessage.Call(dlg.listCtl, _LB_ADDSTRING, 0, strptr(item))
+		sendMessage.Call(dlg.listCtl, win.LB_ADDSTRING, 0, strptr(item))
 	}
 
 	dlg.layout(getDPI(dlg.wnd))
@@ -125,7 +125,7 @@ func (dlg *listDialog) setup(text string, opts options) ([]string, error) {
 		go func() {
 			select {
 			case <-opts.ctx.Done():
-				sendMessage.Call(dlg.wnd, _WM_SYSCOMMAND, _SC_CLOSE, 0)
+				sendMessage.Call(dlg.wnd, win.WM_SYSCOMMAND, _SC_CLOSE, 0)
 			case <-wait:
 			}
 		}()
@@ -142,11 +142,11 @@ func (dlg *listDialog) setup(text string, opts options) ([]string, error) {
 
 func (dlg *listDialog) layout(dpi dpi) {
 	font := dlg.font.forDPI(dpi)
-	sendMessage.Call(dlg.textCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.listCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.okBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.cancelBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.extraBtn, _WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.textCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.listCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.okBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.cancelBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.extraBtn, win.WM_SETFONT, font, 1)
 	setWindowPos.Call(dlg.wnd, 0, 0, 0, dpi.scale(281), dpi.scale(281), _SWP_NOZORDER|_SWP_NOMOVE)
 	setWindowPos.Call(dlg.textCtl, 0, dpi.scale(12), dpi.scale(10), dpi.scale(241), dpi.scale(16), _SWP_NOZORDER)
 	setWindowPos.Call(dlg.listCtl, 0, dpi.scale(12), dpi.scale(30), dpi.scale(241), dpi.scale(164), _SWP_NOZORDER)
@@ -163,41 +163,41 @@ func (dlg *listDialog) layout(dpi dpi) {
 func listProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointer) uintptr {
 	var dlg *listDialog
 	switch msg {
-	case _WM_NCCREATE:
+	case win.WM_NCCREATE:
 		saveBackRef(wnd, *lparam)
 		dlg = (*listDialog)(*lparam)
-	case _WM_NCDESTROY:
+	case win.WM_NCDESTROY:
 		deleteBackRef(wnd)
 	default:
 		dlg = (*listDialog)(loadBackRef(wnd))
 	}
 
 	switch msg {
-	case _WM_DESTROY:
+	case win.WM_DESTROY:
 		postQuitMessage.Call(0)
 
-	case _WM_CLOSE:
+	case win.WM_CLOSE:
 		dlg.err = ErrCanceled
 		destroyWindow.Call(wnd)
 
-	case _WM_COMMAND:
+	case win.WM_COMMAND:
 		switch wparam {
 		default:
 			return 1
 		case win.IDOK, win.IDYES:
 			if dlg.multiple {
-				if len, _, _ := sendMessage.Call(dlg.listCtl, _LB_GETSELCOUNT, 0, 0); int32(len) >= 0 {
+				if len, _, _ := sendMessage.Call(dlg.listCtl, win.LB_GETSELCOUNT, 0, 0); int32(len) >= 0 {
 					dlg.out = make([]string, len)
 					if len > 0 {
 						indices := make([]int32, len)
-						sendMessage.Call(dlg.listCtl, _LB_GETSELITEMS, len, uintptr(unsafe.Pointer(&indices[0])))
+						sendMessage.Call(dlg.listCtl, win.LB_GETSELITEMS, len, uintptr(unsafe.Pointer(&indices[0])))
 						for i, idx := range indices {
 							dlg.out[i] = dlg.items[idx]
 						}
 					}
 				}
 			} else {
-				if idx, _, _ := sendMessage.Call(dlg.listCtl, _LB_GETCURSEL, 0, 0); int32(idx) >= 0 {
+				if idx, _, _ := sendMessage.Call(dlg.listCtl, win.LB_GETCURSEL, 0, 0); int32(idx) >= 0 {
 					dlg.out = []string{dlg.items[idx]}
 				} else {
 					dlg.out = []string{}
@@ -210,7 +210,7 @@ func listProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointer) u
 		}
 		destroyWindow.Call(wnd)
 
-	case _WM_DPICHANGED:
+	case win.WM_DPICHANGED:
 		dlg.layout(dpi(uint32(wparam) >> 16))
 
 	default:
diff --git a/msg_windows.go b/msg_windows.go
index 8923ca9..cb9101a 100644
--- a/msg_windows.go
+++ b/msg_windows.go
@@ -88,9 +88,8 @@ func message(kind messageKind, text string, opts options) error {
 }
 
 func hookMessageDialog(opts options) (unhook context.CancelFunc, err error) {
-	return hookDialog(opts.ctx, opts.windowIcon, nil, func(wnd uintptr) {
-		enumChildWindows.Call(wnd,
-			syscall.NewCallback(hookMessageDialogCallback),
+	return hookDialog(opts.ctx, opts.windowIcon, nil, func(wnd win.HWND) {
+		win.EnumChildWindows(wnd, syscall.NewCallback(hookMessageDialogCallback),
 			uintptr(unsafe.Pointer(&opts)))
 	})
 }
@@ -108,14 +107,14 @@ func hookMessageDialogCallback(wnd win.HWND, lparam *options) uintptr {
 		text = lparam.extraButton
 	}
 	if text != nil {
-		setWindowText.Call(uintptr(wnd), strptr(*text))
+		win.SetWindowText(wnd, syscall.StringToUTF16Ptr(*text))
 	}
 
 	if ctl == 20 /*IDC_STATIC_OK*/ {
 		icon := getIcon(lparam.icon)
 		if icon.handle != 0 {
 			defer icon.delete()
-			sendMessage.Call(uintptr(wnd), _STM_SETICON, icon.handle, 0)
+			win.SendMessage(wnd, win.STM_SETICON, icon.handle, 0)
 		}
 	}
 	return 1
diff --git a/progress_windows.go b/progress_windows.go
index bc83139..0d021d7 100644
--- a/progress_windows.go
+++ b/progress_windows.go
@@ -71,7 +71,7 @@ func (d *progressDialog) Text(text string) error {
 func (d *progressDialog) Value(value int) error {
 	select {
 	default:
-		sendMessage.Call(d.progCtl, _PBM_SETPOS, uintptr(value), 0)
+		sendMessage.Call(d.progCtl, win.PBM_SETPOS, uintptr(value), 0)
 		if value >= d.max {
 			enableWindow.Call(d.okBtn, 1)
 		}
@@ -93,8 +93,8 @@ func (d *progressDialog) Complete() error {
 	select {
 	default:
 		setWindowLong.Call(d.progCtl, intptr(_GWL_STYLE), _WS_CHILD|_WS_VISIBLE|_PBS_SMOOTH)
-		sendMessage.Call(d.progCtl, _PBM_SETRANGE32, 0, 1)
-		sendMessage.Call(d.progCtl, _PBM_SETPOS, 1, 0)
+		sendMessage.Call(d.progCtl, win.PBM_SETRANGE32, 0, 1)
+		sendMessage.Call(d.progCtl, win.PBM_SETPOS, 1, 0)
 		enableWindow.Call(d.okBtn, 1)
 		enableWindow.Call(d.cancelBtn, 0)
 		return nil
@@ -104,7 +104,7 @@ func (d *progressDialog) Complete() error {
 }
 
 func (d *progressDialog) Close() error {
-	sendMessage.Call(d.wnd, _WM_SYSCOMMAND, _SC_CLOSE, 0)
+	sendMessage.Call(d.wnd, win.WM_SYSCOMMAND, _SC_CLOSE, 0)
 	<-d.done
 	if d.err == ErrCanceled {
 		return nil
@@ -179,9 +179,9 @@ func (dlg *progressDialog) setup(opts options) error {
 	centerWindow(dlg.wnd)
 	showWindow.Call(dlg.wnd, _SW_NORMAL, 0)
 	if opts.maxValue < 0 {
-		sendMessage.Call(dlg.progCtl, _PBM_SETMARQUEE, 1, 0)
+		sendMessage.Call(dlg.progCtl, win.PBM_SETMARQUEE, 1, 0)
 	} else {
-		sendMessage.Call(dlg.progCtl, _PBM_SETRANGE32, 0, uintptr(opts.maxValue))
+		sendMessage.Call(dlg.progCtl, win.PBM_SETRANGE32, 0, uintptr(opts.maxValue))
 	}
 	once.Do(dlg.init.Done)
 
@@ -191,7 +191,7 @@ func (dlg *progressDialog) setup(opts options) error {
 		go func() {
 			select {
 			case <-opts.ctx.Done():
-				sendMessage.Call(dlg.wnd, _WM_SYSCOMMAND, _SC_CLOSE, 0)
+				sendMessage.Call(dlg.wnd, win.WM_SYSCOMMAND, _SC_CLOSE, 0)
 			case <-wait:
 			}
 		}()
@@ -208,10 +208,10 @@ func (dlg *progressDialog) setup(opts options) error {
 
 func (d *progressDialog) layout(dpi dpi) {
 	font := d.font.forDPI(dpi)
-	sendMessage.Call(d.textCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(d.okBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(d.cancelBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(d.extraBtn, _WM_SETFONT, font, 1)
+	sendMessage.Call(d.textCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(d.okBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(d.cancelBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(d.extraBtn, win.WM_SETFONT, font, 1)
 	setWindowPos.Call(d.wnd, 0, 0, 0, dpi.scale(281), dpi.scale(133), _SWP_NOZORDER|_SWP_NOMOVE)
 	setWindowPos.Call(d.textCtl, 0, dpi.scale(12), dpi.scale(10), dpi.scale(241), dpi.scale(16), _SWP_NOZORDER)
 	setWindowPos.Call(d.progCtl, 0, dpi.scale(12), dpi.scale(30), dpi.scale(241), dpi.scale(16), _SWP_NOZORDER)
@@ -237,24 +237,24 @@ func (d *progressDialog) layout(dpi dpi) {
 func progressProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointer) uintptr {
 	var dlg *progressDialog
 	switch msg {
-	case _WM_NCCREATE:
+	case win.WM_NCCREATE:
 		saveBackRef(wnd, *lparam)
 		dlg = (*progressDialog)(*lparam)
-	case _WM_NCDESTROY:
+	case win.WM_NCDESTROY:
 		deleteBackRef(wnd)
 	default:
 		dlg = (*progressDialog)(loadBackRef(wnd))
 	}
 
 	switch msg {
-	case _WM_DESTROY:
+	case win.WM_DESTROY:
 		postQuitMessage.Call(0)
 
-	case _WM_CLOSE:
+	case win.WM_CLOSE:
 		dlg.err = ErrCanceled
 		destroyWindow.Call(wnd)
 
-	case _WM_COMMAND:
+	case win.WM_COMMAND:
 		switch wparam {
 		default:
 			return 1
@@ -267,7 +267,7 @@ func progressProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointe
 		}
 		destroyWindow.Call(wnd)
 
-	case _WM_DPICHANGED:
+	case win.WM_DPICHANGED:
 		dlg.layout(dpi(uint32(wparam) >> 16))
 
 	default:
diff --git a/pwd_windows.go b/pwd_windows.go
index 7f1bed4..9bd79d1 100644
--- a/pwd_windows.go
+++ b/pwd_windows.go
@@ -114,7 +114,7 @@ func (dlg *passwordDialog) setup(opts options) (string, string, error) {
 	centerWindow(dlg.wnd)
 	setFocus.Call(dlg.uEditCtl)
 	showWindow.Call(dlg.wnd, _SW_NORMAL, 0)
-	sendMessage.Call(dlg.uEditCtl, _EM_SETSEL, 0, intptr(-1))
+	sendMessage.Call(dlg.uEditCtl, win.EM_SETSEL, 0, intptr(-1))
 
 	if opts.ctx != nil {
 		wait := make(chan struct{})
@@ -122,7 +122,7 @@ func (dlg *passwordDialog) setup(opts options) (string, string, error) {
 		go func() {
 			select {
 			case <-opts.ctx.Done():
-				sendMessage.Call(dlg.wnd, _WM_SYSCOMMAND, _SC_CLOSE, 0)
+				sendMessage.Call(dlg.wnd, win.WM_SYSCOMMAND, _SC_CLOSE, 0)
 			case <-wait:
 			}
 		}()
@@ -139,13 +139,13 @@ func (dlg *passwordDialog) setup(opts options) (string, string, error) {
 
 func (dlg *passwordDialog) layout(dpi dpi) {
 	font := dlg.font.forDPI(dpi)
-	sendMessage.Call(dlg.uTextCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.uEditCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.pTextCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.pEditCtl, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.okBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.cancelBtn, _WM_SETFONT, font, 1)
-	sendMessage.Call(dlg.extraBtn, _WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.uTextCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.uEditCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.pTextCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.pEditCtl, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.okBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.cancelBtn, win.WM_SETFONT, font, 1)
+	sendMessage.Call(dlg.extraBtn, win.WM_SETFONT, font, 1)
 	setWindowPos.Call(dlg.wnd, 0, 0, 0, dpi.scale(281), dpi.scale(191), _SWP_NOZORDER|_SWP_NOMOVE)
 	setWindowPos.Call(dlg.uTextCtl, 0, dpi.scale(12), dpi.scale(10), dpi.scale(241), dpi.scale(16), _SWP_NOZORDER)
 	setWindowPos.Call(dlg.uEditCtl, 0, dpi.scale(12), dpi.scale(30), dpi.scale(241), dpi.scale(24), _SWP_NOZORDER)
@@ -164,24 +164,24 @@ func (dlg *passwordDialog) layout(dpi dpi) {
 func passwordProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointer) uintptr {
 	var dlg *passwordDialog
 	switch msg {
-	case _WM_NCCREATE:
+	case win.WM_NCCREATE:
 		saveBackRef(wnd, *lparam)
 		dlg = (*passwordDialog)(*lparam)
-	case _WM_NCDESTROY:
+	case win.WM_NCDESTROY:
 		deleteBackRef(wnd)
 	default:
 		dlg = (*passwordDialog)(loadBackRef(wnd))
 	}
 
 	switch msg {
-	case _WM_DESTROY:
+	case win.WM_DESTROY:
 		postQuitMessage.Call(0)
 
-	case _WM_CLOSE:
+	case win.WM_CLOSE:
 		dlg.err = ErrCanceled
 		destroyWindow.Call(wnd)
 
-	case _WM_COMMAND:
+	case win.WM_COMMAND:
 		switch wparam {
 		default:
 			return 1
@@ -195,7 +195,7 @@ func passwordProc(wnd uintptr, msg uint32, wparam uintptr, lparam *unsafe.Pointe
 		}
 		destroyWindow.Call(wnd)
 
-	case _WM_DPICHANGED:
+	case win.WM_DPICHANGED:
 		dlg.layout(dpi(uint32(wparam) >> 16))
 
 	default:
diff --git a/util_windows.go b/util_windows.go
index 335f662..a33709f 100644
--- a/util_windows.go
+++ b/util_windows.go
@@ -36,8 +36,6 @@ var (
 	destroyWindow                = user32.NewProc("DestroyWindow")
 	dispatchMessage              = user32.NewProc("DispatchMessageW")
 	enableWindow                 = user32.NewProc("EnableWindow")
-	enumChildWindows             = user32.NewProc("EnumChildWindows")
-	enumWindows                  = user32.NewProc("EnumWindows")
 	getDpiForWindow              = user32.NewProc("GetDpiForWindow")
 	getMessage                   = user32.NewProc("GetMessageW")
 	getSystemMetrics             = user32.NewProc("GetSystemMetrics")
@@ -79,7 +77,7 @@ func hwnd(i uint64) win.HWND { return win.HWND(uintptr(i)) }
 
 func setup() context.CancelFunc {
 	var wnd uintptr
-	enumWindows.Call(syscall.NewCallback(setupEnumCallback), uintptr(unsafe.Pointer(&wnd)))
+	win.EnumWindows(syscall.NewCallback(setupEnumCallback), uintptr(unsafe.Pointer(&wnd)))
 	if wnd == 0 {
 		wnd, _, _ = getConsoleWindow.Call()
 	}
@@ -130,7 +128,7 @@ func setupEnumCallback(wnd uintptr, lparam *uintptr) uintptr {
 	return 1 // continue enumeration
 }
 
-func hookDialog(ctx context.Context, icon any, title *string, init func(wnd uintptr)) (unhook context.CancelFunc, err error) {
+func hookDialog(ctx context.Context, icon any, title *string, init func(wnd win.HWND)) (unhook context.CancelFunc, err error) {
 	if ctx != nil && ctx.Err() != nil {
 		return nil, ctx.Err()
 	}
@@ -149,10 +147,10 @@ type dialogHook struct {
 	done  chan struct{}
 	icon  any
 	title *string
-	init  func(wnd uintptr)
+	init  func(wnd win.HWND)
 }
 
-func newDialogHook(ctx context.Context, icon any, title *string, init func(wnd uintptr)) (*dialogHook, error) {
+func newDialogHook(ctx context.Context, icon any, title *string, init func(wnd win.HWND)) (*dialogHook, error) {
 	tid, _, _ := getCurrentThreadId.Call()
 	hk, _, err := setWindowsHookEx.Call(12, // WH_CALLWNDPROCRET
 		syscall.NewCallback(dialogHookProc), 0, tid)
@@ -181,19 +179,19 @@ func dialogHookProc(code int32, wparam uintptr, lparam *_CWPRETSTRUCT) uintptr {
 	if lparam.Message == 0x0110 { // WM_INITDIALOG
 		tid, _, _ := getCurrentThreadId.Call()
 		hook := (*dialogHook)(loadBackRef(tid))
-		atomic.StoreUintptr(&hook.wnd, lparam.Wnd)
+		atomic.StoreUintptr(&hook.wnd, uintptr(lparam.Wnd))
 		if hook.ctx != nil && hook.ctx.Err() != nil {
-			sendMessage.Call(lparam.Wnd, _WM_SYSCOMMAND, _SC_CLOSE, 0)
+			win.SendMessage(lparam.Wnd, win.WM_SYSCOMMAND, _SC_CLOSE, 0)
 		} else {
 			if hook.icon != nil {
 				icon := getIcon(hook.icon)
 				if icon.handle != 0 {
 					defer icon.delete()
-					sendMessage.Call(lparam.Wnd, _WM_SETICON, 0, icon.handle)
+					win.SendMessage(lparam.Wnd, win.WM_SETICON, 0, icon.handle)
 				}
 			}
 			if hook.title != nil {
-				setWindowText.Call(lparam.Wnd, strptr(*hook.title))
+				win.SetWindowText(lparam.Wnd, syscall.StringToUTF16Ptr(*hook.title))
 			}
 			if hook.init != nil {
 				hook.init(lparam.Wnd)
@@ -217,7 +215,7 @@ func (h *dialogHook) wait() {
 	select {
 	case <-h.ctx.Done():
 		if wnd := atomic.LoadUintptr(&h.wnd); wnd != 0 {
-			sendMessage.Call(wnd, _WM_SYSCOMMAND, _SC_CLOSE, 0)
+			win.SendMessage(win.HWND(wnd), win.WM_SYSCOMMAND, _SC_CLOSE, 0)
 		}
 	case <-h.done:
 	}
@@ -462,7 +460,7 @@ type _CWPRETSTRUCT struct {
 	LParam  uintptr
 	WParam  uintptr
 	Message uint32
-	Wnd     uintptr
+	Wnd     win.HWND
 }
 
 // https://docs.microsoft.com/en-us/windows/win32/api/winuser/ns-winuser-nonclientmetricsw