Restrictions on input and output procedures

Observe these restrictions:

• The procedure must not contain any SORT or MERGE statements.
  Restriction: In an input or output procedure, you can call a program that follows standard linkage conventions. However, the called program cannot issue a SORT, MERGE, RELEASE, or RETURN statement.
• You can use ALTER, GO TO, and PERFORM statements in the procedure to refer to procedure-names outside the input or output procedure. However, control must return to the input or output procedure after a GO TO or PERFORM statement.
• The remainder of the PROCEDURE DIVISION must not contain any transfers of control to points inside the input or output procedure (with the exception of the return of control from a declarative section).
• In an input or output procedure, you can call a program that follows standard linkage conventions. However, the called program cannot issue a SORT or MERGE statement.
• During a SORT or MERGE operation, the SD data item is used. You must not use it in the output procedure before the first RETURN executes. If you move data into this record area before the first RETURN statement, the first record to be returned will be overwritten.
• Language Environment® condition handling does not let user-written condition handlers be established in an input or output procedure.