Using storage functions in C to PL/I ILC

Use the following guidelines when you mix HLL storage constructs and Language Environment storage services:

Storage allocated using the PL/I ALLOCATE statement that:

Is within a PL/I AREA, or
Is of the storage class CONTROLLED, or
Has the REFER option

must be released by the PL/I FREE statement. Storage with these characteristics cannot be released by the Language Environment callable service CEEFRST or by an HLL construct such as the C free() function.

Storage allocated as a result of the PL/I ALLOCATE statement that is of the storage class BASED can be released by CEEFRST or an HLL construct such as the C free() function if the structure:

Is completely declared,
Requires no pad bytes to be added automatically by the compiler, and
Does not contain the REFER option