diff --git a/src/fileio.c b/src/fileio.c
index 48955e0..25706cc 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -6247,7 +6247,7 @@
      * Then truncate what is after the '/', '\' or ':' to 8 characters for
      * MSDOS and 26 characters for AMIGA, a lot more for UNIX.
      */
-    for (ptr = retval + fnamelen; ptr > retval; mb_ptr_back(retval, ptr))
+    for (ptr = retval + fnamelen; ptr > retval; MB_PTR_BACK(retval, ptr))
     {
 	if (*ext == '.'
 #ifdef USE_LONG_FNAME