diff --git a/lib/generate_functions.py b/lib/generate_functions.py
index 89ba562..55e3ef5 100755
--- a/lib/generate_functions.py
+++ b/lib/generate_functions.py
@@ -399,7 +399,16 @@ def parse_header(header_name: str, output_file: str, ext_file: str, prefix: str,
                 ("rlLoadShaderBuffer", "data"),
                 ("rlLoadShaderCode", "vsCode"),
                 ("rlLoadShaderCode", "fsCode"),
-                ("GuiTextInputBox", "secretViewActive")
+                ("GuiTextInputBox", "secretViewActive"),
+                ("GuiSlider", "textLeft"),
+                ("GuiSlider", "textRight"),
+                ("GuiSlider", "value"),
+                ("GuiSliderBar", "textLeft"),
+                ("GuiSliderBar", "textRight"),
+                ("GuiSliderBar", "value"),
+                ("GuiProgressBar", "textLeft"),
+                ("GuiProgressBar", "textRight"),
+                ("GuiProgressBar", "value"),
             ]
 
             zig_type = ziggify_type(arg_name, arg_type, func_name)
diff --git a/lib/raygui.zig b/lib/raygui.zig
index 1489c73..fd0353d 100644
--- a/lib/raygui.zig
+++ b/lib/raygui.zig
@@ -665,17 +665,17 @@ pub fn valueBoxFloat(bounds: Rectangle, text: [:0]const u8, textValue: [:0]u8, v
 }
 
 /// Slider control
-pub fn slider(bounds: Rectangle, textLeft: [:0]const u8, textRight: [:0]const u8, value: *f32, minValue: f32, maxValue: f32) i32 {
+pub fn slider(bounds: Rectangle, textLeft: ?[:0]const u8, textRight: ?[:0]const u8, value: ?*f32, minValue: f32, maxValue: f32) i32 {
     return @as(i32, cdef.GuiSlider(bounds, @as([*c]const u8, @ptrCast(textLeft)), @as([*c]const u8, @ptrCast(textRight)), @as([*c]f32, @ptrCast(value)), minValue, maxValue));
 }
 
 /// Slider Bar control
-pub fn sliderBar(bounds: Rectangle, textLeft: [:0]const u8, textRight: [:0]const u8, value: *f32, minValue: f32, maxValue: f32) i32 {
+pub fn sliderBar(bounds: Rectangle, textLeft: ?[:0]const u8, textRight: ?[:0]const u8, value: ?*f32, minValue: f32, maxValue: f32) i32 {
     return @as(i32, cdef.GuiSliderBar(bounds, @as([*c]const u8, @ptrCast(textLeft)), @as([*c]const u8, @ptrCast(textRight)), @as([*c]f32, @ptrCast(value)), minValue, maxValue));
 }
 
 /// Progress Bar control
-pub fn progressBar(bounds: Rectangle, textLeft: [:0]const u8, textRight: [:0]const u8, value: *f32, minValue: f32, maxValue: f32) i32 {
+pub fn progressBar(bounds: Rectangle, textLeft: ?[:0]const u8, textRight: ?[:0]const u8, value: ?*f32, minValue: f32, maxValue: f32) i32 {
     return @as(i32, cdef.GuiProgressBar(bounds, @as([*c]const u8, @ptrCast(textLeft)), @as([*c]const u8, @ptrCast(textRight)), @as([*c]f32, @ptrCast(value)), minValue, maxValue));
 }