Return Codes from the STAX Service Routine

When your program issues the STAX macro instruction, control is returned to the instruction following the STAX macro instruction. When control is returned, register 1 either contains the address of the user parameter list provided for the previous exit for this task or it contains zero. Register 1 contains zero if this is the first STAX issued for this task, the STAX was issued with a cancel option, or the STAX was issued with only the DEFER option. If an error was detected (return code 8, 12, or 16), then the contents of register 1 is the same as it was at entry.

Table 1. Return codes from the STAX service routine
Return code dec(Hex)	Meaning
0(0)	The STAX service routine successfully completed the function you requested.
4(4)	Deferral of attention exits has already been requested and is presently in effect. Any other operands you specified in the STAX macro instruction have been processed successfully.
8(8)	The user of the DEFER option is not valid (asynchronous exit routine).
12(C)	The STAX macro has already been issued with the IGNORE=YES operand.
16(10)	The STAX macro has already been issued with the IGNORE=NO operand.
20(14)	A branch entry STAX DEFER=NO was requested, but attentions are not being deferred.
24(18)	A branch entry STAX DEFER=NO was requested, but the task is still not eligible to receive attention interruptions.

Note: If the STAX macro instruction is issued by a task that is not executing in a TSO/E user's address space, a return code of zero is passed to the caller in register 15. The contents of register 1 are not altered.

If a combination of parameters or the parameters themselves are not valid, an abend code of X'260' will be issued. The following types of errors cause an abend:

Both DEFER=YES and DEFER=NO are specified.
The input buffer address is not valid because the storage is not in same key as user's TCB.
The input or output buffer size is not valid.
A routine that is not a CLIST attention exit issued the STAX macro with the IGNORE parameter.
A parameter list address is not valid.
The format number of the parameter list is not valid.