Pointer to the User Work Area.

The assembler provides four doublewords of storage for use by the external function. This storage is doubleword aligned and the assembler initializes it to zero for the first call to the external function.

It can be used by the external function to store information (such as the address of acquired storage) between calls. The contents of this storage area are preserved across all call types (SETAF, SETCF, and CLOSE) until the assembly completes. The assembler does not use or modify the work area.