2026-07: LIKE(*EXT): Define a variable like one field in an external file

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2026-07: LIKE(*EXT)

Details

With LIKE(*EXT), you can define an item like one field in an external file.

You don't have to define a file or externally-described data structure if you are only interested in one field from the file.

The field is defined exactly the same as the external field with respect to data type, length, CCSID, etc. For external binary types with zero decimal positions, the EXTBININT setting applies.

The simplest form of LIKE(*EXT) just has two extra parameters:

• The external field name. This can be:
  • The short name (EMPSALARY)
  • The alternate name (EMPLOYEE_SALARY), even if it is quoted ("Employee role")
• The external file name. This is in the usual forms:
  • 'MYFILE'
  • 'MYLIB/MYFILE'
  • '*LIBL/MYFILE'

• Examples with just the field and file parameters: 

  dcl-s salary like(*ext : 'EMPSALARY' : 'EMPLIB');
  dcl-s name like(*ext : 'EMPLOYEE_NAME' : 'EMPLIB');
  dcl-s role like(*ext : '"Employee Role"' : 'EMPLIB');
  

• Examples with the optional record format name. It defaults to the first format if there is more than one format in the file. 

       A          R ORDFMT
       A            TYPE          10A  B  5  2
       A          R ITEMFMT
       A            TYPE           5S 0B  5  2
  
  dcl-s order_type like(*ext : 'TYPE' : 'ORDERDSPF' : ÓRDFMT');
  dcl-s item_type like(*ext : 'TYPE' : 'ORDERDSPF' : 'ITEMFMT');
  

• Examples with length adjustment for string and numeric types. 

   dcl-s bigger_salary like(*ext : 'EMPSALARY' : 'EMPLIB' : +2);
   dcl-s name like(*ext : 'EMPLOYEE_NAME' : 'EMPLIB' : +20);