diff --git a/src/header/getopt/mod.rs b/src/header/getopt/mod.rs
index 5f580381c764911e4985037894a0d0622e3f90a2..66a258f2bdb54663d903f6be850a9f1e195ebd4f 100644
--- a/src/header/getopt/mod.rs
+++ b/src/header/getopt/mod.rs
@@ -88,7 +88,7 @@ pub unsafe extern "C" fn getopt_long(
                                         stdio::fputs(*argv as _, &mut *stdio::stderr);
                                         stdio::fputs(": option '--\0".as_ptr() as _, &mut *stdio::stderr);
                                         stdio::fputs(current_arg, &mut *stdio::stderr);
-                                        stdio::fputs("' requires an argument\n".as_ptr() as _, &mut *stdio::stderr);
+                                        stdio::fputs("' requires an argument\n\0".as_ptr() as _, &mut *stdio::stderr);
                                         return b'?' as c_int;
                                     }
                                 }