--- a/src/header/locale/mod.rs
+++ b/src/header/locale/mod.rs
@@ -111,6 +111,36 @@ pub unsafe extern "C" fn uselocale(newloc: locale_t) -> locale_t {
     old_loc
 }
 
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn getlocalename_l(category: c_int, loc: locale_t) -> *const c_char {
+    if loc.is_null() {
+        return ptr::null();
+    }
+
+    if loc == LC_GLOBAL_LOCALE {
+        if unsafe { GLOBAL_LOCALE.is_null() } {
+            return (&raw const C_LOCALE).cast::<c_char>();
+        }
+
+        let Some(global) = (unsafe { GLOBAL_LOCALE.as_ref() }) else {
+            return ptr::null();
+        };
+        return global
+            .get_name(category)
+            .map_or(ptr::null(), |name| name.as_ptr());
+    }
+
+    if !(LC_COLLATE..=LC_ALL).contains(&category) {
+        return ptr::null();
+    }
+
+    let loc = loc.cast_const().cast::<LocaleData>();
+    let Some(loc) = (unsafe { loc.as_ref() }) else {
+        return ptr::null();
+    };
+    loc.name.as_ptr()
+}
+
 /// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/newlocale.html>.
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn newlocale(mask: c_int, locale: *const c_char, base: locale_t) -> locale_t {