Subroutines in CL

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Subroutines in CL

 

The Subroutine (SUBR) command is used in a CL program or procedure, along with the End Subroutine (ENDSUBR) command, to delimit the group of commands that define a subroutine. The name of the subroutine, as used by the CALLSUBR command, is defined by the SUBR parameter on the SUBR command.

 Return Subroutine (RTNSUBR)

PGM

CallSubr subr(Validate)
 
SUBR Validate 
      
Chgvar &Errors 0                                                   
                                                                   
Chkobj &epBldPgm  (*Pgm)                                           
Monmsg CPF9800  exec(Do)                                           
  chgvar &Errors -1                                                
  chgvar &Errormsg  ('Report Build pgm:' *bcat %Trim(&epBldpgm) +  
                     *bcat ' does not exist')                      
  Rtnsubr                                                          
EndDo                                                              
 Chkobj &epAPILib  (*Lib)                                         
 Monmsg CPF9800  exec(Do)                                         
   chgvar &Errors -1                                              
   chgvar &Errormsg  ('API library:' *bcat %Trim(&epAPILib) +     
                      *bcat ' does not exist')                    
   Rtnsubr                                                        
 EndDo                                                            
ENDSUBR 


EndPgm       

The following example is about the general structure of a CL procedure that contains a subroutine.

              PGM    
              DCLPRCOPT  SUBRSTACK(25)
              DCL        VAR(&RTNVAR) TYPE(*INT) LEN(4)        
			       :
              CALLSUBR   SUBR(SUBR1) RTNVAL(&RTNVAR)
			       :
              SUBR       SUBR(SUBR1)                            
			       :
              RTNSUBR    RTNVAL(-1)
			       :
              ENDSUBR                                                                                                         
              ENDPGM 

In this example, the Declare Processing Options (DCLPRCOPT) command was used to specify the size of the subroutine stack to be 25. The variable &RTNVAR is used to contain the return value from the subroutine. The CALLSUBR command will transfer control to the subroutine SUBR1, as defined by the SUBR command. If the RTNSUBR command is run, the value of &RTNVAR will be -1, if the ENDSUBR command is run, &RTNVAR will equal 0. If no RTNVAL parameter was defined on the CALLSUBR command, the return value from the subroutine would be ignored.

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