If you do not code a value on the PATHOPTS parameter or if you do not code a PATHOPTS on a DD statement with a PATH parameter, the system assumes that the pathname exists, searches for it, and issues a message if the pathname does not exist.

If the file exists and you specify PATHOPTS without a file-option for the access group, the allocation succeeds assuming ORDONLY. If the file does not exist and you specify PATHOPTS without a file-option from the access group, the system fails to open the file and issues a message.