Example of passing a file and passing a data structure with the associated variables.

The following example shows you how to define a data structure to hold the associated variables for a file, how to pass the file and the data structure as parameters to a procedure, and how to use the parameters within the procedure.

Figure 41. /COPY file INFILE_DEFS 
 * The /COPY file has template definitions for the File and Associated Variables

 /if defined(FILE_DEFINITIONS)

 // Template for the "INFILE" file type
Finfile_t  if   e             disk    template block(*yes)
F                                     extdesc('MYLIB/MYFILE')
 /eof
 /endif

 /if defined(DATA_DEFINITIONS)

 // Template for the associated variables for an INFILE file 
D infileVars_t    ds                  qualified template 
D    filename                   21a
D    mbrname                    10a

 // Prototype for a procedure to open an INFILE file 
D open_infile     pr
D    theFile                          likefile(infile_t)
D    kwVars                           likeds(infileVars)
D                                     options(*nullind)
 /eof
 /endif
Figure 42. The calling procedure that passes the file parameter 
P myproc          b
 // Copy in the template and prototype definitions
 /define FILE_DEFINITIONS
 /COPY INFILE_DEFS
 /undefine FILE_DEFINITIONS

 /define DATA_DEFINITIONS
 /COPY INFILE_DEFS
 /undefine DATA_DEFINITIONS

 // Define the file using LIKEFILE, to enable it to be passed as 
 // a parameter to the "open_infile" procedure.

 // Define all the associated variables as subfields of a data
 // structure, so that all the associated variables can be
 // passed to the procedure as a single parameter
Ffile1                                likefile(infile_t) 
F                                     extfile(file1Vars.filename)
F                                     extmbr(file1Vars.mbrname)
F                                     usropn

D file1Vars       ds                  likeds(infileVars_t) 

  /free
         open_infile (file1 : file1Vars);

         . . .
Figure 43. The called procedure that uses the file parameter 
 // Copy in the template and prototype definitions
 /define FILE_DEFINITIONS
 /COPY INFILE_DEFS
 /undefine FILE_DEFINITIONS

 /define DATA_DEFINITIONS
 /COPY INFILE_DEFS
 /undefine DATA_DEFINITIONS

P open_infile     b
 // The open_infile procedure has two parameters
 //  - a file
 //  - a data structure containing all the associated variables for the file
D open_infile     pi
D    theFile                          likefile(infile_t)
D    kwVars                           likeds(infileVars)
  /free
         // The %OPEN(filename) built-in function reflects the 
         // current state of the file
         if not %open(theFile);
            // The called procedure modifies the calling procedure's "file1Vars" 
            // variables directly, through the passed parameter
            kwVars.extfile = 'LIB1/FILE1';
            kwVars.extmbr = 'MBR1';
            // The OPEN operation uses the file1Vars subfields in the 
            // calling procedure to open the file, opening file LIB1/FILE1(MBR1)
            open theFile;
         endif;
         . . .

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