DCLOPT(*NOCHGDSLEN

The DCLOPT keyword specifies options related to declarations.

The parameter must be *NOCHGDSLEN.

When DCLOPT(*NOCHGDSLEN) is specified, you can use %SIZE with a data structure parameter in a free-form File or Definition statement if the following conditions are met:
  • All the subfields are defined.
  • If the data structure is defined with the DIM or OCCURS keyword, the dimension must be defined when %SIZE appears.
  • The usage of %SIZE and the data structure definition must be either both in the global declarations or both in the same subprocedure.
The following additional rules apply:
  • A data structure cannot be specified on an Input specification.
  • If a data structure appears in the result field of a Calculation specification, the Length entry cannot be specified.
  • If an externally-described file has Input or Output specifications generated, a field name in the file cannot be the name of a data structure. (Input and Output specifications are generated for any global file that does not have the QUALIFIED or LIKEFILE keyword.)
In the following example,
  1. Keyword DCLOPT(*NOCHGDSLEN) is specified in the Control statement.
  2. The data structure MYDS is defined without an explicit length.
  3. Subfield DATA is defined like LINE.
  4. The first file declaration is not valid because the value of %SIZE(MYDS) is not yet known.
  5. When field LINE is defined, all the subfields of MYDS are defined, and due to the presence of DCLOPT(*NOCHGDSLEN) in the Control statement, data structure MYDS is defined and its size is known.
  6. The second file declaration is valid because the value of %SIZE(MYDS) is known.

Without DCLOPT(*NOCHGDSLEN), neither file declaration would be valid because the size of MYDS would not be known until the compiler had processed all the statements of the procedure. 


ctl-opt dclopt(*nochgdslen); // 1 

dcl-ds myDs; // 2 
  seq zoned(6:2);
  dat zoned(6);
  data like(line); // 3 
end-ds;

dcl-f myfile1 disk(%size(myDS)); // 4 

dcl-s line char(100); // 5 

dcl-f myfile2 disk(%size(myDS)); // 6