The VTAM® authorized path macroinstructions can be executed asynchronously (OPTCD=ASY) or synchronously (OPTCD=SYN) under control of a service request block (SRB), or a task control block (TCB). Table 1 shows the coding requirements for VTAM authorized path, including the VTAM authorized path macroinstructions and the supervisor macroinstructions needed to execute the authorized path through VTAM. Consult the z/OS MVS Programming: Authorized Assembler Services Guide for information on coding the supervisor macroinstructions described in Table 1.

To use authorized path while running under a TCB, the authorized program, having put itself into supervisor state, specifies BRANCH=YES on any RPL-based macroinstruction that is to be executed using authorized path.

Authorized path is always used when an RPL-based macroinstruction is issued under the control of an SRB. A task identification and address space identification should be specified in the SRB as discussed in Task association; otherwise (RTNCD,FDB2)=(X'14',X'55') could result. One way to gain control under an SRB is for the authorized program, while running under a TCB, to specify an RPL exit routine when issuing (in supervisor state) an RPL-based macroinstruction that specifies BRANCH=YES. On entry to the RPL exit routine, the program is running under an SRB. Any RPL-based macroinstruction issued under an SRB is automatically executed using authorized path; BRANCH=YES need not be specified. An alternative way to create the SRB environment is to use the MVS™ SCHEDULE macroinstruction.