Defining the DSECTs
Control block formats and DSECTs, and Specifying a session parameter, show the DSECT fields and equated values generated by the macroinstructions. These are the DSECT-creating macroinstructions:
Control block/data area | DSECT name and operands | Appendix |
---|---|---|
ACB | IFGACB AM=VTAM®[,DSECT=YES|NO] | E |
EXLST | IFGEXLST AM=VTAM[,DSECT=YES|NO] | E |
RPL | IFGRPL AM=VTAM[,DSECT=YES|NO] | E |
Device characteristics field in NIB | ISTDVCHR [DSECT=YES|NO] | E |
Processing options field in NIB | ISTDPROC [DSECT=YES|NO] | E |
Reason codes for RTNCD-FDB2-FDBK fields in RPL | ISTUSFBC | E |
NIB | ISTDNIB | E |
Session parameter | ISTDBIND | F |
Program operator message and command header | ISTDPOHD | L |
Request/response header | ISTRH | E |
Buffer-list entry | ISTBLENT | E |
Application-supplied dial parameters | ISTASDP | E |
Access-method-support vector list | ISTAMSVL | E |
Resource-information vector list | ISTRIVL | E |
Application-ACB vector list | ISTVACBV | E |
In coding these macroinstructions, follow these rules:
- Specify AM=VTAM as an operand for IFGACB, IFGRPL, and IFGEXLST. This distinguishes these DSECTs from similar DSECTs generated for VSAM.
- Code DSECT=NO as an operand if the DSECT assembler instruction is to be suppressed for IFGACB, IFGEXLST, IFGRPL, ISTDPROC, or ISTDVCHR. This allows the fields generated by these macroinstructions to be concatenated to the current CSECT or DSECT. See Example 3 in GENCB macroinstruction.
- Follow the macroinstruction with a CSECT assembler instruction or another DSECT assembler instruction unless it is the last instruction before ending the program or unless the map is to be extended intentionally. (A terminal work area could be mapped following IFGRPL, for example.)
- Ensure that no labels that are generated or reserved for future
use are used elsewhere in the program.
Other areas of the program use the following labels. Therefore, the application program should not use them:
ACB DEV NIB RPL
ASD EXL POH RSV
BIN IFG PRO USF
BLE IST RHASD