Using OPS/REXX › OPS/REXX Instructions › OPTIONS Instruction › Usage Notes for OPTIONS Instructions

Usage Notes for OPTIONS Instructions

Keep these guidelines in mind when you specify the OPTIONS instruction:

• In an OPTIONS instruction containing the OPSWXTRN keyword, the complete OPSWXTRN keyword phrase must appear on a single OPTIONS source line. In fact, we strongly recommend that OPTIONS instructions that contain OPSWXTRN keywords contain no other OPTIONS keywords.
• Because OPSWXTRN keywords are analyzed during the compile phase, no REXX substitution can be performed.
• When specifying the OPSWXTRN keyword in an OPTIONS instruction, the name represents the name of an external subroutine whose presence in the environment is optional and whose absence is accounted for by the program logic. The value of name must be a valid member name from 1 to 8 characters in length.

  Note: The validity of name is not checked; however, invalid member names simply waste space in an internal table.

  Some syntax errors in OPTIONS instructions that contain the OPSWXTRN keyword are flagged only during execution. See the following example.

• Regardless of whether the OPSWXTRN keyword is used, if an external REXX subroutine will ever be called at execution time, its source code must be available at compile time.
• External load modules and product built-in functions can be resolved just prior to execution and do not need to be present at compile time.
• A maximum of 24 unresolved external subroutine names are permitted in a main program or AOF rule (or any of its external subroutines). If you specify more than 24 unresolved external subroutine names, CA OPS/MVS ignores the extra ones and issues warning message OPS0924W.
• If an unresolved external subroutine is called, CA OPS/MVS issues message OPS0992E, and the REXX program terminates with error 43 to indicate that the routine was not found. The SYNTAX handler can trap this error at execution time.
• OPTIONS instructions are reprocessed during execution. Therefore, for performance reasons, it is not a good idea to place these OPTIONS instructions in a repetitive code path (for example, in a DO loop). This is true for all OPTIONS instructions, unless for some reason dynamic substitution needs to be used repetitively.
• Options that correspond to OSF server limit parameters cannot be used to selectively override the OSF server limit parameter. For example, REXX option NOMAXTIME will not override the server OSFRUN limit. The OPS/REXX options are designed to selectively override the OPS/REXX default value parameters such as REXXMAXSECONDS.