fix: VarChar handling raw string, VarChar Inz silent drop

rpgrt/src/lib.rs

@@ -11,6 +11,8 @@
 //! | `rpg_dsply_cstr`    | `(ptr: *const c_char)`                 | Display a null-terminated C string   |
 //! | `rpg_dsply_i64`     | `(n: i64)`                             | Display a signed 64-bit integer      |
 //! | `rpg_dsply_f64`     | `(f: f64)`                             | Display a double-precision float     |
+//! | `rpg_dsply_read`    | `(prompt: *const c_char, response: *mut i64)` | Display null-term prompt & read i64 |
+//! | `rpg_dsply_read_len`| `(ptr: *const u8, len: i64, response: *mut i64)` | Display length-delimited prompt & read i64 |
 //! | `rpg_halt`          | `(code: i32)`                          | Abnormal program termination         |
 //! | `rpg_char_i64`      | `(n: i64) -> *const c_char`            | Format integer as null-term C string |
 //! | `rpg_concat`        | `(a: *const c_char, b: *const c_char) -> *const c_char` | Concatenate two C strings |
@@ -209,6 +211,59 @@ pub unsafe extern "C" fn rpg_dsply_read(
     }
 }
 
+// ─────────────────────────────────────────────────────────────────────────────
+// rpg_dsply_read_len — display a length-delimited prompt and read a response
+// ─────────────────────────────────────────────────────────────────────────────
+
+/// Three-operand DSPLY where the prompt is a fixed-length (or VarChar) field
+/// passed as `(ptr, len)` rather than a null-terminated C string.
+///
+/// This is called when the prompt operand is a `Char` or `VarChar` variable —
+/// those are stored as raw byte buffers with no null terminator, so
+/// `rpg_dsply_read` (which calls `CStr::from_ptr`) cannot be used safely.
+///
+/// Trailing ASCII spaces are stripped from the prompt before display, matching
+/// the behaviour of `rpg_dsply`.
+///
+/// # Safety
+///
+/// * `ptr` must be valid for at least `len` bytes (or be null).
+/// * `response` must be a valid, writable `i64` pointer.
+#[no_mangle]
+pub unsafe extern "C" fn rpg_dsply_read_len(
+    ptr: *const u8,
+    len: i64,
+    response: *mut i64,
+) {
+    use std::io::BufRead;
+
+    // Build the prompt string the same way rpg_dsply does.
+    let bytes = if ptr.is_null() || len <= 0 {
+        b"" as &[u8]
+    } else {
+        unsafe { slice::from_raw_parts(ptr, len as usize) }
+    };
+    let trimmed = rtrim_spaces(bytes);
+    let text = String::from_utf8_lossy(trimmed);
+
+    {
+        let stdout = io::stdout();
+        let mut out = stdout.lock();
+        let _ = writeln!(out, "DSPLY  {}", text);
+        let _ = out.flush();
+    }
+
+    // Read one line from stdin and parse it as i64.
+    let stdin = io::stdin();
+    let mut line = String::new();
+    if stdin.lock().read_line(&mut line).is_ok() {
+        let trimmed_line = line.trim();
+        if let Ok(n) = trimmed_line.parse::<i64>() {
+            unsafe { *response = n; }
+        }
+    }
+}
+
 // ─────────────────────────────────────────────────────────────────────────────
 // rpg_halt — abnormal termination
 // ─────────────────────────────────────────────────────────────────────────────