diff -r a12e102ff67f -r 7bc999fe285d src/buffer.c
--- a/src/buffer.c	Sun Mar 23 11:28:20 2025 +0100
+++ b/src/buffer.c	Sun Mar 23 12:26:03 2025 +0100
@@ -139,6 +139,7 @@
             npos = 0;
             break;
         default:
+            errno = EINVAL;
             return -1;
     }