Fix defaults (windows).

color_windows.go

@@ -46,7 +46,7 @@ func selectColor(options []Option) (color.Color, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if opts.ctx != nil || opts.title != "" {
+	if opts.ctx != nil || opts.title != nil {
 		unhook, err := hookDialogTitle(opts.ctx, opts.title)
 		if err != nil {
 			return nil, err

file_windows.go

@@ -28,8 +28,8 @@ func selectFile(options []Option) (string, error) {
 	args.StructSize = uint32(unsafe.Sizeof(args))
 	args.Flags = 0x81008 // OFN_NOCHANGEDIR|OFN_FILEMUSTEXIST|OFN_EXPLORER
 
-	if opts.title != "" {
+	if opts.title != nil {
-		args.Title = syscall.StringToUTF16Ptr(opts.title)
+		args.Title = syscall.StringToUTF16Ptr(*opts.title)
 	}
 	if opts.showHidden {
 		args.Flags |= 0x10000000 // OFN_FORCESHOWHIDDEN
@@ -76,8 +76,8 @@ func selectFileMutiple(options []Option) ([]string, error) {
 	args.StructSize = uint32(unsafe.Sizeof(args))
 	args.Flags = 0x81208 // OFN_NOCHANGEDIR|OFN_ALLOWMULTISELECT|OFN_FILEMUSTEXIST|OFN_EXPLORER
 
-	if opts.title != "" {
+	if opts.title != nil {
-		args.Title = syscall.StringToUTF16Ptr(opts.title)
+		args.Title = syscall.StringToUTF16Ptr(*opts.title)
 	}
 	if opts.showHidden {
 		args.Flags |= 0x10000000 // OFN_FORCESHOWHIDDEN
@@ -149,8 +149,8 @@ func selectFileSave(options []Option) (string, error) {
 	args.StructSize = uint32(unsafe.Sizeof(args))
 	args.Flags = 0x88808 // OFN_NOCHANGEDIR|OFN_PATHMUSTEXIST|OFN_NOREADONLYRETURN|OFN_EXPLORER
 
-	if opts.title != "" {
+	if opts.title != nil {
-		args.Title = syscall.StringToUTF16Ptr(opts.title)
+		args.Title = syscall.StringToUTF16Ptr(*opts.title)
 	}
 	if opts.confirmOverwrite {
 		args.Flags |= 0x2 // OFN_OVERWRITEPROMPT
@@ -229,8 +229,8 @@ func pickFolders(opts options, multi bool) (str string, lst []string, err error)
 		return "", nil, syscall.Errno(hr)
 	}
 
-	if opts.title != "" {
+	if opts.title != nil {
-		ptr := syscall.StringToUTF16Ptr(opts.title)
+		ptr := syscall.StringToUTF16Ptr(*opts.title)
 		dialog.Call(dialog.vtbl.SetTitle, uintptr(unsafe.Pointer(ptr)))
 	}
 
@@ -319,8 +319,8 @@ func browseForFolder(opts options) (string, []string, error) {
 	var args _BROWSEINFO
 	args.Flags = 0x1 // BIF_RETURNONLYFSDIRS
 
-	if opts.title != "" {
+	if opts.title != nil {
-		args.Title = syscall.StringToUTF16Ptr(opts.title)
+		args.Title = syscall.StringToUTF16Ptr(*opts.title)
 	}
 	if opts.filename != "" {
 		ptr := syscall.StringToUTF16Ptr(opts.filename)

msg_windows.go

@@ -17,9 +17,9 @@ func message(kind messageKind, text string, options []Option) (bool, error) {
 	var flags uintptr
 
 	switch {
-	case kind == questionKind && opts.extraButton != "":
+	case kind == questionKind && opts.extraButton != nil:
 		flags |= 0x3 // MB_YESNOCANCEL
-	case kind == questionKind || opts.extraButton != "":
+	case kind == questionKind || opts.extraButton != nil:
 		flags |= 0x1 // MB_OKCANCEL
 	}
 
@@ -35,14 +35,14 @@ func message(kind messageKind, text string, options []Option) (bool, error) {
 	}
 
 	if kind == questionKind && opts.defaultCancel {
-		if opts.extraButton == "" {
+		if opts.extraButton == nil {
 			flags |= 0x100 // MB_DEFBUTTON2
 		} else {
 			flags |= 0x200 // MB_DEFBUTTON3
 		}
 	}
 
-	if opts.ctx != nil || opts.okLabel != "" || opts.cancelLabel != "" || opts.extraButton != "" {
+	if opts.ctx != nil || opts.okLabel != nil || opts.cancelLabel != nil || opts.extraButton != nil {
 		runtime.LockOSThread()
 		defer runtime.UnlockOSThread()
 
@@ -53,10 +53,15 @@ func message(kind messageKind, text string, options []Option) (bool, error) {
 		defer unhook()
 	}
 
+	var title *uint16
+	if opts.title != nil {
+		title = syscall.StringToUTF16Ptr(*opts.title)
+	}
+
 	activate()
 	s, _, err := messageBox.Call(0,
 		uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(text))),
-		uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(opts.title))), flags)
+		uintptr(unsafe.Pointer(title)), flags)
 
 	if opts.ctx != nil && opts.ctx.Err() != nil {
 		return false, opts.ctx.Err()
@@ -81,14 +86,14 @@ func hookMessageLabels(kind messageKind, opts options) (unhook context.CancelFun
 				getClassName.Call(wnd, uintptr(unsafe.Pointer(&name)), uintptr(len(name)))
 				if syscall.UTF16ToString(name[:]) == "Button" {
 					ctl, _, _ := getDlgCtrlID.Call(wnd)
-					var text string
+					var text *string
 					switch ctl {
 					case 1, 6: // IDOK, IDYES
 						text = opts.okLabel
 					case 2: // IDCANCEL
 						if kind == questionKind {
 							text = opts.cancelLabel
-						} else if opts.extraButton != "" {
+						} else if opts.extraButton != nil {
 							text = opts.extraButton
 						} else {
 							text = opts.okLabel
@@ -96,8 +101,8 @@ func hookMessageLabels(kind messageKind, opts options) (unhook context.CancelFun
 					case 7: // IDNO
 						text = opts.extraButton
 					}
-					if text != "" {
+					if text != nil {
-						ptr := syscall.StringToUTF16Ptr(text)
+						ptr := syscall.StringToUTF16Ptr(*text)
 						setWindowText.Call(wnd, uintptr(unsafe.Pointer(ptr)))
 					}
 				}

notify_windows.go

@@ -29,8 +29,10 @@ func notify(text string, options []Option) error {
 	info := syscall.StringToUTF16(text)
 	copy(args.Info[:len(args.Info)-1], info)
 
-	title := syscall.StringToUTF16(opts.title)
+	if opts.title != nil {
-	copy(args.InfoTitle[:len(args.InfoTitle)-1], title)
+		title := syscall.StringToUTF16(*opts.title)
+		copy(args.InfoTitle[:len(args.InfoTitle)-1], title)
+	}
 
 	switch opts.icon {
 	case InfoIcon:
@@ -71,8 +73,8 @@ func wtsMessage(text string, opts options) error {
 	}
 
 	title := opts.title
-	if title == "" {
+	if title == nil {
-		title = "Notification"
+		title = stringPtr("Notification")
 	}
 
 	timeout := zenutil.Timeout
@@ -81,7 +83,7 @@ func wtsMessage(text string, opts options) error {
 	}
 
 	ptext := syscall.StringToUTF16(text)
-	ptitle := syscall.StringToUTF16(title)
+	ptitle := syscall.StringToUTF16(*title)
 
 	var res uint32
 	s, _, err := wtsSendMessage.Call(

util_windows.go

@@ -138,11 +138,15 @@ func hookDialog(ctx context.Context, initDialog func(wnd uintptr)) (unhook conte
 	}, nil
 }
 
-func hookDialogTitle(ctx context.Context, title string) (unhook context.CancelFunc, err error) {
+func hookDialogTitle(ctx context.Context, title *string) (unhook context.CancelFunc, err error) {
-	return hookDialog(ctx, func(wnd uintptr) {
+	var init func(wnd uintptr)
-		ptr := syscall.StringToUTF16Ptr(title)
+	if title != nil {
-		setWindowText.Call(wnd, uintptr(unsafe.Pointer(ptr)))
+		init = func(wnd uintptr) {
-	})
+			ptr := syscall.StringToUTF16Ptr(*title)
+			setWindowText.Call(wnd, uintptr(unsafe.Pointer(ptr)))
+		}
+	}
+	return hookDialog(ctx, init)
 }
 
 type _COMObject struct{}