After DFHZNEP receives control from DFHZNAC, it obtains
the address of the communication area by means of an ADDRESS
COMMAREA API command.
Figure 1 illustrates the general structure of the communication area. Figure 1. General structure of the communication area
The significance of each section of the communication area is described here:
Header
A 4-byte header common to all user-replaceable programs.
Error_being_processed
Identifiers of the error code and the terminal associated with the error.
User option bytes
Flags that indicate the default actions set by DFHZNAC, and that may be reset within
DFHZNEP.
z/OS® Communications Server information
Sense and RPL codes.
Additional info. for NEP
Other useful information for the NEP.
Additional system parameters
Locations of indirect parameters, such as the TCTTE, and other system information.
XRF parameters
Recovery notification data. The fields in TWAXRNOT can be reset by the NEP
A detailed listing of the communication area is given
in Figure 2. Figure 2. The
DFHZNAC/DFHZNEP communication area (part 1)
**************************************************************************
** Header **
** These fields are READ ONLY **
**************************************************************************
NEPCAHDR DS 0XL4 Standard Header
NEPCAFNC DS XL1 Function Code Always '1'
NEPCACMP DS XL2 Component Code Always 'ZC'
DS XL1 Reserved
**************************************************************************
** Error_being_processed **
** Identity of terminal and the error code associated with it **
** These fields are READ ONLY **
**************************************************************************
TWAEC DS XL1 Error Code
DS CL3 Reserved
TWANID DS CL4 Terminal identity
TWANETN DS CL8 Netname
**************************************************************************
** User option bytes **
** Initially set to the default actions. **
** DFHZNEP can change the defaults. **
**************************************************************************
TWAOPTL DS 0XL3 User option bytes
TWAOPT1 DS XL1 User option byte 1
TWAOPT2 DS XL1 User option byte 2
TWAOPT3 DS XL1 User option byte 3
DS XL1 Reserved
Figure 3. The DFHZNAC/DFHZNEP communication area (part 2)
**************************************************************************
** z/OS Communications Sever information - Any sense and RPL codes **
** These fields are READ ONLY **
**************************************************************************
TWAVTAM DS 0XL12 z/OS Communications Sever information
TWARPLCD DS H z/OS Communications Sever RPL feedback codes
DS H Reserved
TWASENSS DS 0F Sense codes to be sent
TWASS1 DS XL1 System sense byte No 1
TWASS2 DS XL1 System sense byte No 2
TWAUS1 DS XL1 User sense byte No 1
TWAUS2 DS XL1 User sense byte No 2
*
TWASENSR DS 0F Sense codes received
TWASR1 DS X System sense byte No 1
TWASR2 DS X System sense byte No 2
TWAUR1 DS X User sense byte No 1
TWAUR2 DS X User sense byte No 2
*
**************************************************************************
** Additional information for the NEP **
**Except for TWANPFW, TWANLD, and TWANLDL these fields are READ ONLY **
**************************************************************************
TWAADINF DS 0XL22
DS F Reserved
TWACTLB DS X General use control byte
* EQU X'80' Reserved
* EQU X'40' Reserved
TWACSC EQU X'20' Clear sense code indicator
TWAPSC EQU X'10' Print z/OS Communications Sever sense codes
TWATIOA EQU X'08' Print portion of I/O area
* EQU X'04' Reserved
TWAVTRTC EQU X'02' z/OS Communications Sever return code available
TWANEPR DS XL1 NEP return code byte
TWANPFW EQU X'80' Retry write with FORCE=YES
TWAREASN DS XL1 z/OS Communications Sever reason code
TWASTAT DS XL1 z/OS Communications Sever status code
TWATRSN DS XL1 CICS terminal control
* terminal error code
TWAXRSN DS Exception response seq number recd
TWAR EQU *
TWAPFLG DS XL1 CLSDST pass flag
TWAPIP EQU X'80' CLSDST pass in progress
TWANEPC DS XL1 NEP class flag
TWAEISAB DS XL1 Stand-alone begin bracket indicator
TWAESAB EQU X'04' Stand-alone begin bracket
DS XL3 Reserved
TWANLD DS A Address of data to be logged
TWANLDL DS H Length of data to be logged
Figure 4. The DFHZNAC/DFHZNEP communication area (part 3)
**************************************************************************
** Additional system parameters **
** Except for TWAPNETN, TWAPNTID, TWAUPRRC these fields are READ ONLY **
**************************************************************************
TWASYSPM DS 0XL68
TWATCTA DS AL4 Address of TCTTE being processed
TWARPL DS AL4 Address of z/OS Communications Sever RPL
TWATIOAA DS AL4 Address of data portion of TIOA
TWATIOAL DS H Length of data portion of TIOA
TWACOMML DS H Length of commarea data for TCTTE
TWACOMMA DS CL4 Address of commarea data for TCTTE
TWATECIA DS AL4 Address of TCTTE user area
TWATECIL DS H Length of TCTTE user area
TWAPPNTN DS CL8 Primary 3270 printer netname
TWAPPTID DS CL4 Primary 3270 printer termid
TWAPPELG DS X Primary printer eligible indicator
TWAPPELY EQU X'01' Primary printer is eligible flag
TWASPNTN DS CL8 Secondary 3270 printer netname
TWASPTID DS CL4 Secondary 3270 printer termid
TWASPELG DS X Secondary printer eligible indicator
TWASPELY EQU X'01' Secondary printer is eligible flag
TWAPNETN DS CL8 Selected 3270 printer netname
TWAPNTID DS CL4 Selected 3270 printer termid
TWAUPRRC DS B Unavailable Printer return code
TWAUPRNP EQU X'00' No printer selected
TWAUPRPS EQU X'01' Printer selected
TWAUPRDD EQU X'FF' Data disposal complete
TWAUPRPE EQU X'FE' Error on Put request
TWAERRF1 DS B Error flag byte 1
TWALXS EQU X'80' Logon crossed simlogon
DS XL2 Reserved
**************************************************************************
** XRF parameters **
** XRF recovery notification data **
** DFHZNEP can change these default actions **
**************************************************************************
TWAXRNOT DS X Recovery notification options
TWAXRNON EQU X'80' Recov notification = none
TWAXRMSG EQU X'40' Recov notification = message
TWAXRTRN EQU X'20' Recov notification = transact.
DS XL3 Reserved
TWAXMSTN DS CL8 Recovery mapset name
TWAXMAPN DS CL8 Recovery map name
TWAXTRAN DS CL4 Recovery transaction ID
*
The next sections describe fields in the parameter list
that can be reset within DFHZNEP. See also Coding for the 3270 ‘unavailable printer' condition, which describes the use of the
flags in the “unavailable printer return code” field.
