There are some restrictions when these procedures are used.
(i) The Procedure should not contain any SORT/MERGE statement.
(ii) An explicit transfer of the control outside the procedures is not permitted.
(iii) The control should reach the statements only through related SORT statement.
(iv) The Procedure should consist of one or more sections and they should appear contiguously in the body of the program.
(v) The input and output procedure should not share any section or any part between them.