*OMIT vs *NOPASS: Understanding the Key Differences - IBM i

*OMIT v/s *NOPASS

In RPGLE, *OMIT and *NOPASS are the two options used to specify the optional parameters for the procedures. It is essential to understand the difference between *OMIT and *NOPASS because knowing which keyword to use for the specific case helps in writing the clean code. 

Before we jump on to the key differences, let's have a look at the use of each of the keywords.

*OMIT

By using the *OMIT on the parameter while declaring a procedure, we can make this parameter an optional parameter. 

We could either pass the data to this parameter or simply pass '*OMIT' to while calling the procedure. 

Dcl-PR SampleProcedure;                                 MandatoryParameter1 Char(1);                          OptionalParameterWithOmit Char(1) Options(*Omit);     MandatoryParameter2 Packed(1);                      End-PR;                                                                                                     Dcl-Proc SampleProcedure Export;                        Dcl-PI SampleProcedure;                                 MandatoryParameter1 Char(1);                          OptionalParameterWithOmit Char(1) Options(*Omit);     MandatoryParameter2 Packed(1);                      End-PI;                                                                              // Code to be run in the procedure                                                   End-Proc;

This procedure can be called in one of the two ways,

• Either by passing the data for the optional parameter. 
• Or by passing '*OMIT' to avoid passing this parameter. 

// Passing the data SampleProcedure('A' : 'B' : 1);                       // Passing *Omit SampleProcedure('A' : *Omit : 1);

*NOPASS

By using the *NOPASS on the parameter while declaring a procedure, we can make this parameter an optional parameter. 

We could either pass the data to this parameter or not pass this parameter at all while calling the procedure. 

Dcl-PR SampleProcedure;                                     MandatoryParameter1 Char(1);                              MandatoryParameter2 Packed(1);                            OptionalParameterWithNoPass Char(1) Options(*NoPass);   End-PR;                                                                                                             Dcl-Proc SampleProcedure Export;                            Dcl-PI SampleProcedure;                                     MandatoryParameter1 Char(1);                              MandatoryParameter2 Packed(1);                            OptionalParameterWithNoPass Char(1) Options(*NoPass);   End-PI;                                                                                                             // Code to be run in the procedure;                                                                             End-Proc;

This procedure can be called in one of the two ways,

• Either by passing the data for the optional parameter. 
• Or by not passing the parameter at all.

// Passing the data SampleProcedure('A' : 1 : 'B');                       // Not passing the optional parameter SampleProcedure('A' : 1);

The Difference

There are couple of main differences between using *OMIT and *NOPASS. 

• *OMIT can be used on any parameter, whereas *NOPASS can only be used on the last parameter(s) i.e., no mandatory parameter can be declared after *NOPASS is specified. 
• *OMIT needs to passed to avoid passing the parameter declared with *OMIT, whereas no parameter needs to be passed when specified using *NOPASS (considering it is the last parameter). 

I hope this post has help in understanding what is the use of *OMIT, *NOPASS and the difference. 

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