COBCH1698 Use of CONSTANT qualifier must match for parameter and prototype

A CONSTANT item has not been declared consistently when used with a prototype.

If a CALL statement includes a CONSTANT parameter, and a matching call prototype is defined, the equivalent parameter in the prototype must also include the CONSTANT clause (see p1 in the prototype); also, if the clause is used on a data item in a call prototype, the CONSTANT clause must also be specified for the corresponding parameter used in the sub-program (see p1 of subprog2).

       program-id prototype is external.
       linkage section.
       01 p1 pic x(10). *> constant needed
       01 p2 pic x(10) constant.
       entry "subprog1" using reference p1.
       entry "subprog2" using reference p2.
       end program.
       program-id. prog1.
       01 a1 pic x(10) constant value "abcdefghij".
          call "subprog1" using reference a1
       end program.
       program-id. "subprog2".
       linkage section.
       01 p1 pic x(10). *> constant needed
       procedure division using p1.
           goback.
       end program.