Host variable declarations can be made at the same places as ordinary PL/I variable declarations.
Not all PL/I data types are acceptable for host variables. The precompiler does not use the data attribute defaults specified in the PL/I DEFAULT statement. If the declaration for a variable is not recognized, any statement that references the variable may result in the message "The host variable token ID is not valid".
The SQL precompiler uses only the names and data attributes of host variable declarations; the alignment, scope, and storage class attributes are ignored.