Identify LVGL methods that return pointers

[C47D]

I'm not very fluent in Rust (still can't figure out ownership) but this change made lv_label_get_text available:

diff --git a/lvgl/src/widgets/label.rs b/lvgl/src/widgets/label.rs
index 691ffb8..5235f86 100644
--- a/lvgl/src/widgets/label.rs
+++ b/lvgl/src/widgets/label.rs
@@ -1,5 +1,6 @@
 use crate::widgets::Label;
 use crate::{LabelLongMode, NativeObject};
+use cstr_core::CStr;
 
 #[cfg(feature = "alloc")]
 mod alloc_imp {
@@ -41,4 +42,10 @@ impl Label<'_> {
     pub fn get_long_mode(&self) -> u8 {
         unsafe { lvgl_sys::lv_label_get_long_mode(self.raw().as_ref()) }
     }
+
+    pub fn get_text(&self) -> &'static str {
+        let char_ptr = unsafe { lvgl_sys::lv_label_get_text(self.raw().as_ref()) };
+        let c_str = unsafe { CStr::from_ptr(char_ptr) };
+        c_str.to_str().unwrap_or_default()
+    }
 }

And I'm using it like this

diff --git a/examples/demo.rs b/examples/demo.rs
index f69cf5b..dba4865 100644
--- a/examples/demo.rs
+++ b/examples/demo.rs
@@ -62,6 +62,8 @@ fn main() -> Result<(), LvError> {
     bt.set_height(80);
     bt.set_recolor(true);
     bt.set_align(Align::TopLeft, 0, 0);
+    let mut test_label = Label::from("701");
+    println!("Label get_text from bindinig: {:?}", test_label.get_text());
 
     let mut power: Label = "#fade2a 20%#".into();
     power.set_recolor(true);
diff --git a/lvgl/src/widgets/label.rs b/lvgl/src/widgets/label.rs
index 691ffb8..5235f86 100644
--- a/lvgl/src/widgets/label.rs
+++ b/lvgl/src/widgets/label.rs

You can see the '701' being printed here:

Do you think this is correct @AlixANNERAUD ?

This is a memory safety issue, since get_text returns a &'static str, as it directly points to the label's text buffer, assuming the string is valid UTF-8.
However, when the label text is modified in LVGL, LVGL likely reallocates the buffer, invalidating the pointer/reference—this behavior contradicts the static reference lifetime.
To address this, the function should either be marked as unsafe (with appropriate documentation) or return an owned string instead. For instance:

String::from_utf8_lossy(cstr.to_bytes()).to_string()

Originally posted by @AlixANNERAUD in #162 (comment)

[C47D]

We need to identify methods that return pointers so we either document them as unsafe or handle them properly. This might be possible by using the #191 request where adding support for generation of methods that return something is being handled.

What do you think @AlixANNERAUD ?

[AlixANNERAUD]

Yes, that can be easily identified with syn::Type::Ptr. These should follow the same rules :

• Try with zero copy / reference and safe way.
• If not possible (eg label text where the lifetime is not guaranteed ), do it the unsafe way (zero copy). And maybe propose a safe with copy alternative