--- src/os_unix.c	Tue May  1 09:52:21 2012
+++ src/os_unix.c	Tue May  1 09:52:24 2012
@@ -2509,7 +2509,7 @@
 	}
 
 	l = STRLEN(buf);
-	if (l >= len)
+	if (l >= len - 1)
 	    retval = FAIL;
 #ifndef VMS
 	else