some \0 aka nul bytes in &str are deleted ...

...before sending the &str to ncurses backend,
this is done for cursive's print_at() and print_at_rep() only!
otherwise, nothing would get printed, silently.

Why delete \0 instead of replace with eg. space?
this explains it best:
gyscos#778 (comment)

This also fixes warnings about unused Result.

Closes: gyscos#780

cursive/src/backends/curses/n.rs

@@ -6,6 +6,7 @@ pub use ncurses;
 use log::{debug, warn};
 use ncurses::mmask_t;
 
+use std::borrow::Cow;
 use std::cell::{Cell, RefCell};
 use std::ffi::CString;
 use std::fs::File;
@@ -398,22 +399,53 @@ impl backend::Backend for Backend {
         ncurses::refresh();
     }
 
-    fn print_at(&self, pos: Vec2, text: &str) {
-        ncurses::mvaddstr(pos.y as i32, pos.x as i32, text);
+    fn print_at<'a>(&self, pos: Vec2, text: &'a str) {
+        // Remove '\0' from &str or else nothing would get printed
+        // As for why delete instead of replace with eg. space, see:
+        // https://github.com/gyscos/cursive/pull/778#discussion_r1613859129
+        let text = &delete_nuls(text);
+        let len = text.len() as i32;
+        // Ignore the value to avoid warning: unused `Result` that must be used
+        let _ = ncurses::mvaddnstr(pos.y as i32, pos.x as i32, text.as_ref(), len);
     }
 
     fn print_at_rep(&self, pos: Vec2, repetitions: usize, text: &str) {
+        // Remove '\0' from &str or else nothing would get printed
+        let text = &delete_nuls(text);
+        let len = text.len() as i32;
         if repetitions > 0 {
-            ncurses::mvaddstr(pos.y as i32, pos.x as i32, text);
+            let _ = ncurses::mvaddnstr(pos.y as i32, pos.x as i32, text, len);
             let mut dupes_left = repetitions - 1;
             while dupes_left > 0 {
-                ncurses::addstr(text);
+                let _ = ncurses::addnstr(text, len);
                 dupes_left -= 1;
             }
         }
     }
 }
 
+#[inline(always)]
+fn delete_nuls<'a>(text: &'a str) -> Cow<'a, str> {
+    let text: Cow<'a, str> = if text.contains('\0') {
+        Cow::Owned(text.replace('\0', ""))
+    } else {
+        Cow::Borrowed(text)
+    };
+    text
+}
+
+#[test]
+fn test_print_at_rep_nul_char_in_string() {
+    let text = "Some\0thing with \0nul\0s\0 in \0it";
+    let expected = "Something with nuls in it";
+    assert_eq!(expected, delete_nuls(text));
+
+    let backend = Backend::init().unwrap();
+    // These don't panic, they replace the \0-es with nothing
+    backend.print_at(Vec2::new(10, 10), "abc\0de\0f");
+    backend.print_at_rep(Vec2::new(10, 10), 10, "abc\0de\0f");
+}
+
 /// Returns the Key enum corresponding to the given ncurses event.
 fn get_mouse_button(bare_event: i32) -> MouseButton {
     match bare_event {