Manipulative macroinstruction errors and special conditions

Table 1. Manipulative macroinstructions: Return code values and meanings
Reg	Contents	Meaning
0	X'08'	GENCB can fail because of insufficient storage; request can be reissued later
15	X'00'	Manipulative macroinstruction operation is successful
15	X'04'	Specific error in register 0 (examining return code for SHOWCB or TESTCB does not require examining a control block). Return codes for manipulative macroinstructions shows the possible register 0 settings and their meanings.
15	X'08'	Attempt is made to use execute form of the macroinstruction to enter a new item in parameter list being modified (only existing items can be modified)

Figure 1 shows how manipulative macroinstruction error and special-condition information is organized. All other manipulative macroinstruction errors and special conditions are due to faulty logic and require program termination and debugging.

Figure 1. How manipulative-macroinstruction error and special-condition information is organized

The diagram shows after a GENCB, MODCB, SHOWCB, or TESTCB, return code 0 in register 15 indicates the macroinstruction is successful; otherwise, it is unsuccessful. If the macroinstruction fails with X'04' in register 15, check register 0 for error return code. Appendix I describes the return codes. If a TESTCB fails, control is passed to the specified address of an ERET routine. See Chapter 13 for details about the TESTCB macroinstuction.