All MiNT traps are now guaranteed not to be used by future versions of GEMDOS (or more accurately, are guaranteed not to be used in non-compatible ways by future versions of GEMDOS). So checking for -32 return codes to see if a function is present is kosher. Of course, there are other things (like how Fread and Fwrite will behave) that you may want to check the MiNT cookie for... Eric