Parameters

When the external function or subroutine gets control, register 1 points to the external function parameter list (EFPL). Table 1 describes the parameter list. TSO/E provides a mapping macro, IRXEFPL, for the external function parameter list. The mapping macro is in SYS1.MACLIB.

Table 1. External function parameter list
Offset (decimal)	Number of bytes	Description
0	4	Reserved.
4	4	Reserved.
8	4	Reserved.
12	4	Reserved.
16	4	An address that points to the parsed argument list. Each argument is represented by an address/length pair. The argument list is terminated by X'FFFFFFFFFFFFFFFF'. Table 1 shows the format of the argument list. If there were no arguments included on the function or subroutine call, the address points to X'FFFFFFFFFFFFFFFF'.
20	4	An address that points to a fullword. The fullword contains the address of an evaluation block (EVALBLOCK). You use the evaluation block to return the result of the function or subroutine. Table 1 describes the evaluation block.