Purpose

$ASSIGN obtains a channel number, and associates a (previously created) mailbox with the channel.

In X.25 programs, you use $ASSIGN to assign a channel to the NW device.

In an X.29 program, you use $ASSIGN to assign a channel to the NW device or to the NV device.

When your program attempts to assign a channel to NWA0: or NVA0: X.25 for OpenVMS creates a new device called NWAuu: or NVAuu: (where uu is a unique unit number), and assigns the channel to that device. $ASSIGN never assigns a channel to NWA0: or NVA0: .

You will use the number allocated to the NW device in all QIOs which communicate with a remote DTE. In X.29 programs, you will need to supply the number of the NV device as the p6 parameter in all QIO calls to the NW device. Use $GETDVI to discover the unit number allocated to the NV or NW device.

Note that your program must assign only one channel for each virtual circuit to the NWAuu device.

In X.25 programs, for a Permanent Virtual Circuit (PVC) you assign a channel to the device NWA0: (exactly as for an SVC), and then specify the name of the PVC in the NCB for the $QIO(IO$_ACCESS) service.

Format

$ASSIGN devnam,chan,[acmode],[mbxnam]

Arguments

Example

In the following example, the device name is referred to by PSI_DEV. The channel to the network device is placed in PSI_CHAN. A mailbox, MBX, is assigned to this channel. No access mode is specified.

;Declaring the data:
PSI_DEV:
         .ASCID  /_NWA0:/     ; Network device name
PSI_CHAN:
         .BLKW   1            ; Mailbox channel
MBX:
         .ASCID  /SYS$NET/    ; Mailbox logical name
; Using the System Service:
$ASSIGN_S -                   ; Assign a channel
          DEVNAM = PSI_DEV,-  ; to network device
          CHAN = PSI_CHAN,-   ; Channel number
          MBXNAM = MBX        ; Mailbox name

Return Status

Purpose

The $CANCEL system service cancels all pending I/O requests on the specified channel. This has the effect of clearing the virtual call in progress on the channel.

You can cancel I/O requests only from an access mode equal to, or more privileged than, the access mode from which you originally assigned the channel.

When a request currently in progress is canceled, the driver is notified immediately. The action taken for I/O requests in progress is similar to that taken for queued requests:

Outstanding I/O requests are automatically canceled at image exit.

Format

$CANCEL chan

Arguments

Example

In this example, the call cancels all pending I/O requests to the network device on channel PSI_CHAN.

; Declaring the data:
PSI_CHAN:
         .BLKW   1             ; Mailbox channel
; Using the System Service
$CANCEL_S -                    ; Cancel I/O requests
          CHAN = PSI_CHAN      ; on channel

Return Status

Purpose

$CREMBX creates a virtual mailbox device named MBAuu:, and assigns an I/O channel to it.

The system provides the unit number, uu , when it creates the mailbox MBAuu:. If a mailbox with the specified name already exists, $CREMBX assigns a channel to the that mailbox. It should not however be used to create a channel to the mailbox SYS$NET as $CREMBX does not recognize SYS$NET as an existing mailbox.

Format

$CREMBX [prmflg],chan,[maxmsg],[bufquo],[promsk],[acmode], [lognam]

Arguments

Example

In this example $CREMBX is used to create a network device mailbox and assign the network channel MBX_CHAN.

MBX_CHAN:
  .BLKW  1                      ; Channel to mailbox
MBX_NAME:
  .ASCID  /X29_MBX/             ; Mailbox name
;+
; Create network device mailbox and assign network channel.
;-
  $CREMBX_S -                   ; Create mailbox
    CHAN = MBX_CHAN,-           ; channel
    LOGNAM = MBX_NAME           ; logical name
  BSBW ERROR                    ; Check for error

Return Status

Purpose

$DASSGN deassigns the logical channel to an NV or NW device.

For channels assigned to NV devices, $DASSGN takes the following action:

Format

$DASSGN chan

Arguments

Example

In the following example, channel PSI_CHAN is deassigned.

; Declaring the data:
PSI_CHAN:
           .BLKW   1             ; Mailbox channel
; Using the System Service:
$DASSGN_S -                      ; Deassign channel
          CHAN = PSI_CHAN        ; to network device

Return Status

Purpose

In X.25 programs, you can use $GETDVI to obtain the NW unit number (see the section called “$GETDVI - Get NW or NV Unit Number”).

In X.29 programs, you can use $GETDVI to:

$GETDVI - Get NW or NV Unit Number

NV_CHAN:
  .BLKW  1                      ; Channel to NV
UNIT_LIST:
  .WORD  4                      ; length (in bytes) of buffer
                                ; for $GETDVI to output
  .WORD  DVI$_UNIT              ; item code
  .LONG  NV_UNIT                ; Address of buffer for $GETDVI
                                ; to output
  .LONG  NV_UNIT_LENGTH         ; Address of word for $GETDVI
                                ; to put the amount of data output
  .LONG 0                       ; End of the item-list
IO_STATUS:
  .BLKW 4                       ;I/O Status block
;+
; Get the unit number of the NV device.
;-
  $GETDVIW_S -                  ; Use this routine to convert
    -                           ; the channel number given to
    -                           ; a unit number.
    CHAN = NV_CHAN,-            ; channel
    ITMLST = UNIT_LIST          ; Address of item-list of information.
    -                           ; wanted from system service.
    IOSB = IO_STATUS            ; Status return
  BSBW ERROR                    ; Check for error

$GETDVI - Get Remote DTE Address of PAD Connected to NV

PAD_REMDTE_LENGTH: .blkw 1      ; Length of returned string
PAD_REMDTE:    .BLKB 64         ; Storage To hold the remote DTE address in
NV_CHAN:
  .BLKW  1                      ; Channel to NV
REMDTE_LIST:
  .WORD  64                     ; length (in bytes) of buffer
                                ; for $GETDVI to output
  .WORD  DVI$_TT_ACCPORNAM      ; item code
  .LONG  PAD_REMDTE             ; Address of buffer for $GETDVI
                                ; to output
  .LONG  PAD_REMDTE_LENGTH      ; Address of word for $GETDVI
                                ; to put the amount of data output
  .LONG  0                      ; End of the item-list
IO_STATUS:
  .BLKW  4                      ;I/O Status block
;+
; Get the remote DTE address of the PAD
;-
  $GETDVIW_S -                  ; Use this routine to obtain
    -                           ; the local DTE class and
    -                           ; remote DTE.
    CHAN = NV_CHAN,-            ; channel
    ITMLST = REMDTE_LIST        ; Address of item-list of information.
    -                           ; wanted from system service.
    IOSB = IO_STATUS            ; Status return
  BSBW ERROR                    ; Check for error

Purpose

The QIO system service with a function code of IO$_ACCESS requests a virtual circuit to be set up, and can optionally request network facilities. If you subscribe to the fast select facility, up to 128 bytes of data can be sent with the request rather than being limited to 16 bytes of data for normal calls. You must also use this service before data can be transmitted or received on a PVC.

For an SVC, the service completes when the request is either accepted or rejected by the remote DTE. For a PVC, the call completes without any PSDN activity.

If there is a mailbox associated with the NW device, an NCB is written to the mailbox with details of the call acceptance or call rejection. Call accept messages have the code MSG$_CONNECT, and reject messages have the code MSG$_ DISCONNECT.

If the rights identifier PSI$X25_USER is defined on your system, your program must possess either that rights identifier or BYPASS privilege.

If PSI$X25_USER is not defined on your system, your program must possess NETMBX privilege.

Note that to set up a virtual circuit requires certain system resources, which are deducted from the quota for your process. Refer to the VSI X.25 for OpenVMS Programming Guide for details.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], [p1],p2,[p3],[p4],[p5],p6

Arguments

NCB Contents

Only mandatory, optional, and ignore items are listed in the following table. Other items will generate an error if you use them.

Notes

Examples

X.25 Code Example In this example, the system service, IO$_ACCESS, is called to set up a virtual circuit. The channel to the network device is PSI_CHAN. The I/O Status Block is declared as IO_STATUS, and the address of a descriptor of the NCB to be used is ACCESS_NCB.

; Declaring the data:
PSI_CHAN:
           .BLKW   1                ; Mailbox channel
IO_STATUS:
           .BLKW   4                ; I/O status block
ACCESS_NCB:
           .LONG ACCESS_NCB_LEN     ; NCB descriptor
           .ADDRESS ACCESS_NCB_BLK
; Using the System Service:
$QIOW_S -                      ; Issue QIO and wait
        CHAN = PSI_CHAN,-      ; to network device
        FUNC = #IO$_ACCESS,-   ; Function is make call
        IOSB = IO_STATUS,-     ; I/O status block
        P2 = #ACCESS_NCB       ; Address of call NCB
                               ; descriptor
P6 = 0                         ; NV device unit number
                               ; is zero for NW

X.29 Code Example In this example, the system service IO$_ACCESS is called to set up a virtual circuit for an X.29 call. The channel to the network device is NW_CHAN. The I/O Status Block is declared as IO_STATUS, and the address of a descriptor of the NCB to be used is ACCESS_NCB.

NW_CHAN:
  .BLKW   1     ; Channel to NW
NV_UNIT:
  .BLKL   1     ; NV Unit number
IO_STATUS:
  .BLKW   4     ;I/O Status block
;+
; Network Connect Block:
;-
ACCESS_NCB:   ; NCB Descriptor
  .LONG    ACCESS_NCB_LEN
  .ADDRESS  ACCESS_NCB_BLK
ACCESS_NCB_BLK:   ; NCB to set up a call
  DTECLASS:   ; DTE Class
  .WORD  DTECLASS_LEN
  .WORD  PSI$C_NCB_DTECLASS
  .ASCIC  /ISO8208/
  DTECLASS_LEN = .-DTECLASS
REMOTE_DTE:   ; DTE Address
  .WORD  REMOTE_DTE_LEN
  .WORD  PSI$C_NCB_REMDTE
  .ASCIC  /23427341234522/
  REMOTE_DTE_LEN = .-REMOTE_DTE
          ; NO user data
          ; NO fast select
  ACCESS_NCB_LEN = .-ACCESS_NCB_BLK
;+
; Set up a virtual call
;-
  $QIOW_S -   ; Issue QIO and wait
    CHAN = NW_CHAN,-  ; to network device
    FUNC = #IO$_ACCESS,- ; function is make call
    IOSB = IO_STATUS,-  ; I/O status block
    P2 = #ACCESS_NCB,-  ; address of call NCB
    P6 = NV_UNIT  ; NV unit number
  BSBW IO_ERROR   ; Check for I/O error

Return Status

Secondary Status Values

The secondary status values are found in the third word of the IOSB.

For OpenVMS VAX, if the first word of the IOSB contains SS$_NORMAL, the third word can have one or more of the following flags set:

If the first word of the IOSB contains SS$_ABORT or SS$_IVDEVNAM, the third word can contain one of the status values shown in the following table.

Purpose

$QIO(IO$_ACCESS!IO$M_ABORT) rejects an incoming request to set up a virtual circuit.

If you subscribe to the fast select facility, you can use this call to send user data.

Note that you are advised to use the incoming call’s NCB as argument p2 to this QIO. Find the NCB in the mailbox associated with the channel that received the call. If you do not use the NCB as p2 , the incoming call identifier must be copied from the incoming NCB.

If the rights identifier PSI$X25_USER is defined on your system, your program must possess either that rights identifier or BYPASS privilege.

If PSI$X25_USER is not defined on your system, your program must possess NETMBX privilege.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], [p1],p2,[p3],[p4],[p5],[p6]

Arguments

NCB Contents

Only mandatory, optional, and ignore items are listed in the following table. Other items will generate an error if you use them.

Notes

Example

In the following example, IO$_ACCESS!IO$M_ABORT rejects the request. The channel to the network device is PSI_CHAN and the NCB descriptor begins at ABORT_NCB.

; Declaring the data:
PSI_CHAN:
           .BLKW   1                  ; Mailbox channel
ABORT_NCB:
           .BLKQ   1                  ; NCB descriptor
; Using the System Service:
$QIOW_S -                                ; Issue QIO and wait
        CHAN = PSI_CHAN,-                ; to the network device
        FUNC = #IO$_ACCESS!IO$M_ABORT,-  ; Function is reject
                                         ; request
        P2 = #ABORT_NCB                  ; NCB descriptor address

Return Status

Purpose

$QIO(IO$_ACCESS!IO$M_ACCEPT) accepts an incoming request from a remote DTE (X.25) or a remote PAD (X.29) to set up a virtual circuit.

The parameters requested in the incoming call can be negotiated using this QIO function. Parameter negotiation can be achieved either by specifying individual items to be negotiated or by specifying the items in a template (see NCB TEMPLATE item code). Note that if a template is not defined, the Default template is used.

A template can also be used to supply parameters that are not defined in the NCB used to accept the call.

If you subscribe to the fast select acceptance facility, you can use this call to send user data.

Note that you are advised to use the NCB received as argument p2. Otherwise, you should copy the incoming call identifier (PSI$C_NCB_ICI) from the received NCB. Read the NCB in the mailbox associated with the channel that received the call.

If the rights identifier PSI$X25_USER is defined on your system, your program must possess either that rights identifier or BYPASS privilege.

If PSI$X25_USER is not defined on your system, your program must possess NETMBX privilege.

Note that to accept a request to set up a virtual circuit requires certain system resources which are deducted from the quota for your process. See the VSI X.25 for OpenVMS Programming Guide for details.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], [p1],p2,[p3],[p4],[p5],p6

Arguments

NCB Contents

Only mandatory, optional, and ignored items are listed in the following table. Other items will generate an error if you use them.

Notes

Examples

In the following example, the request to set up a virtual circuit is accepted with the IO$_ACCESS!IO$M_ACCEPT call. The channel to the network device is PSI_CHAN. An I/O status block, IO_STATUS, is to receive the completion status, and the starting address of the descriptor of the NCB is ACCEPT_NCB.

; Declaring the data:
PSI_CHAN:
           .BLKW   1                 ; Mailbox channel
IO_STATUS:
           .BLKW   4                 ; I/O status block
ACCEPT_NCB:
           .BLKQ   1                 ; NCB descriptor
; Using the System Service:
$QIOW_S -                                 ; Issue QIO and wait
        CHAN = PSI_CHAN,-                 ; to the network device
        FUNC = #IO$_ACCESS!IO$M_ACCEPT,-  ; Function is accept call
        IOSB = IO_STATUS,-                ; I/O status block
        P2 = ACCEPT_NCB                   ; NCB descriptor address

In the following example, the request to set up a virtual circuit is accepted with the IO$_ACCESS!IO$M_ACCEPT call. The channel to the network device is NW_CHAN. NV_UNIT supplies the NV device number. An I/O status block, IO_STATUS, is to receive the completion status, and the starting address of the descriptor of the NCB is ACCEPT_NCB.

NW_CHAN:
  .BLKW   1                     ; Channel to NW
NV_UNIT:
  .BLKL   1                     ; NV Unit number
IO_STATUS:
       .BLKW   4                ; IO Status block
;+
; Network Connect Block:
;-
ACCEPT_NCB:                     ; NCB Descriptor
  .BLKL   2
;+
; Accept a virtual call
;-
$QIOW_S -                              ; Issue QIO and wait
  CHAN = NW_CHAN,-                     ; to network device
  FUNC = #IO$_ACCESS!IO$M_ACCEPT,-     ; function is accept call
  IOSB = IO_STATUS,                    ; I/O status block
  P2 = #ACCESS_NCB,-                   ; address of call NCB
  P6 = NV_UNIT                         ; NV unit number
  BSBW IO_ERROR                        ; Check for I/O error

Return Status

Purpose

$QIO(IO$_ACCESS!IO$M_REDIRECT) redirects an incoming call request to another process before the call request is accepted or rejected.

The call uses the subaddress and other addressing information specified in the NCB in the normal way, to associate the new process with the call.

The system service completes when X.25 for OpenVMS redirects the incoming call request.

Note that you are advised to use the NCB received as argument p2. Otherwise, you should copy the incoming call identifier (PSI$C_NCB_ICI) from the received NCB. Read the NCB in the mailbox associated with the channel that received the call.

To ensure that your process is not searched again, move the priority value from PSI$C_NCB_FLT_PRI to PSI$C_NCB_FLT_REDPRI.

If the rights identifier PSI$X25_USER is defined on your system, your program must possess either that rights identifier or BYPASS privilege.

If PSI$X25_USER is not defined on your system, your program must possess NETMBX privilege.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], [p1],p2,[p3],[p4],[p5],[p6]

Arguments

NCB Contents

Only mandatory, optional, and ignored items are listed in the following table. Other items will generate an error if you use them.

Example

In this example the QIO is used with function code IO$ACCESS!IO$M_ REDIRECT, to redirect the call according to the parameters in the NCB REDIRECT_NCB.

; Declaring the data:
PSI_CHAN:
           .BLKW   1                  ; Mailbox channel
IO_STATUS:
           .BLKW   1                  ; I/O status block
REDIRECT_NCB:
           .BLKQ   1                  ; NCB descriptor
; Using the System Service:
$QIOW_S -                                   ; Issue QIO and wait
        CHAN = PSI_CHAN,-                   ; to the network device
        FUNC = #IO$_ACCESS!IO$M_REDIRECT,-  ; Function is
                                            ; redirect call
        IOSB = IO_STATUS,-                  ; I/O status block
        P2 = REDIRECT_NCB                   ; NCB descriptor address

Return Status

Purpose

$QIO(IO$_ACPCONTROL) allows the current process to select which incoming calls it handles.

The request can specify a number of parameters to identify the incoming calls it will handle, and these parameters form an X25 ACCESS FILTER entity for your process. These parameters are shown in Table 2.2, “Item Codes for a Network Process Declaration Block”.

Further filters can be added by issuing more than one QIO with a function code of IO$_ACPCONTROL, but you cannot change the information associated with an existing filter.

Filters can be deleted without stopping your process, by deassigning the channel over which $QIO(IO$_ACPCONTROL) was issued.

For information about displaying the filters in the X25 Access module, see VSI X.25 for OpenVMS Management Guide.

All incoming calls whose parameters match those specified in this QIO are placed in the mailbox associated with the channel over which this QIO request was issued.

Details of the network process declaration block contents are given below.

Format

$QIO [efn],chan,func, [iosb],[astadr],[astprm], p1,p2,[p3],[p4], [p5],[p6]

Arguments

.BYTE NFB$C_DECLNAME
.LONG 0

Network Process Declaration Block

Each type of data has a specific format: single–byte value, counted string, or longword value. Table 2.2, “Item Codes for a Network Process Declaration Block” summarizes the permitted type codes.

Notes

Examples

X.25 Code Example In the following example, the 5–byte function control block is at address FUNC_BUF. The descriptor of the network process declaration block is at address DEC_BUF. The channel to the network device is PSI_CHAN.

  ; Declaring the data:
  PSI_CHAN:
             .BLKW   1                  ; Mailbox channel
  IO_STATUS:
             .BLKQ   1                  ; I/O status block
  FUNC_DESC:                            ;Function block descriptor
            .LONG   5                   ;Length
            .ADDRESS FUNC_BUF           ;Address
  FUNC_BUF:                             ;Function block
            .BYTE NFB$C_DECLNAME
            .LONG   0
  DEC_DESC:                             ;Declaration descriptor
            .LONG   DEC_BUF_LEN         ;Length
            .ADDRESS DEC_BUF            ;Address
  DEC_BUF:                              ;Declaration block
  ACCLVL:
            .WORD   ACCLVL_LEN          ;Length field
            .WORD   PSI$C_NTD_ACCLVL    ;Type field
            .ASCIC  "X25L3"             ;String
  ACCLVL_LEN =  .-ACCLVL
  ;Item list to match called address extension of A15
  ;
  EXTMSK:    .WORD   EXTMSK_LEN         ;Item length
             .WORD   PSI$C_NTD_EXTMSK   ;Item type
             .BYTE   EXTMSK_COUNT       ;Byte count for "counted
                                        ;string"
EXTMSK_STR: .BYTE   3                   ;Semi-octet count
             .BYTE   ^FF                ;First two semi-octets
             .BYTE   ^XF0               ;Third semi-octet
EXTMSK_COUNT=.-EXTMSK_STR
EXTMSK_LEN  =.-EXTMSK
EXTVAL:    .WORD   EXTVAL_LEN           ;Item length
           .WORD   PSI$C_NTD_EXTVAL     ;Item type
           .BYTE   EXTVAL_COUNT         ;Byte count for "counted
                                        ;string"
EXTVAL_STR: .BYTE 3                     ;Count in semi-octets
            .BYTE ^XA1                  ;First two semi-octets
            .BYTE ^X50                  ;Third semi-octet/
  EXTVAL_COUNT=.-EXTVAL_STR
  EXTVAL_LEN =.-EXTVAL
DEC_BUF_LEN =.-DEC_BUF
; Using the System Service:
$QIOW_S -                        ; Issue QIO and wait
        CHAN = PSI_CHAN,-        ; to the network device
        FUNC = #IO$_ACPCONTROL-  ; Function is ACP control
        IOSB = IO_STATUS,-       ; I/O status block
        P1 = FUNC_DESC,-         ; Function descriptor address
        P2 = #DEC_DESC           ; Process declaration
                                 ; descriptor address

X.29 Code Example In this example, the QIO with function code IO$_ ACPCONTROL is used to tell X.25 for OpenVMS to accept all X.29 calls. The 5– byte function control block is at address DECL_BUF. The descriptor of the network process declaration block is at address NPDB_DESC. The channel to the network device is NW_CHAN.

NW_CHAN:
  .BLKW  1                      ; Channel to NW
DECL_DESC:
  .LONG  5                      ; Five byte buffer
  .ADDRESS DECL_BUF             ; Address of buffer
DECL_BUF:
  .BYTE  NFB$C_DECLNAME         ; function type
  .LONG  0                      ; parameter
NPDB_DESC:                      ; Network Process Declaration
                                ; Buffer descriptor
  .LONG NPD_BUF_LEN             ; Size of buffer
  .ADDRESS NPD_BUF              ; Address of buffer
NPD_BUF:
NPD_ITEM1:
  .WORD  NPD_ITEM1_LEN          ; Length of first item
  .WORD  PSI$C_NTD_ACCLVL       ; Access Level
  .ASCIC  /X29/                 ; ASCII counted string
NPD_ITEM1_LEN = . - NPD_ITEM1   ; Calculate the size in words
NPD_BUF_LEN = . - NPD_BUF
;+
; Tell X.25 that we want to accept all X29 calls
;-
  $QIOW_S -                     ; Send a QIO and wait
    IOSB = IO_STATUS,-          ; I/O status block
    CHAN = NW_CHAN,-            ; NW channel
    FUNC = #IO$_ACPCONTROL,-    ; function is write
    P1 = DECL_DESC,-            ; descriptor of declname block
    P2 = #NPDB_DESC             ; descriptor of declaration block
  BSBW  IO_ERROR                ; Check system service and IOSB

Return Status

Secondary Status Values

Purpose

The QIO system service with a function code of IO$_DEACCESS clears a switched virtual circuit or confirms receipt of a call cleared message. For PVCs, this call closes the virtual circuit so that the PVC can be reassigned to another process.

Note that clearing a virtual circuit can result in loss of data in either direction (see the VSI X.25 for OpenVMS Programming Guide for details).

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], [p1],[p2],[p3],[p4],[p5],p6

Arguments

NCB Contents

Only mandatory, optional, and ignored items are listed in the following table. Other items will generate an error if you use them.

Notes

Examples

X.25 Code Example In this example the system service QIO is used with function code IO$_DEACCESS to clear the virtual circuit. The channel to the network device is PSI_CHAN.

; Declaring the data:
PSI_CHAN:
           .BLKW   1            ; Mailbox channel
IO_STATUS:
           .BLKW   4            ; I/O status block
CLEAR_NCB_DESC:
           .LONG   CLR_NCB_LEN  ; NCB length
           .ADDRESS CLR_NCB     ; NCB address
; Using the System Service:
$QIOW_S -                       ; Issue QIO and wait
         CHAN = PSI_CHAN,-      ; to the network device
         FUNC = #IO$_DEACCESS,- ; Function is clear call
         IOSB = IO_STATUS,-     ; I/O status block
         P2   = #CLEAR_NCB_DESC ; NCB descriptor address

X.29 Code Example In this example the system service QIO is used with function code IO$_DEACCESS to clear the virtual circuit. The channel to the network device is PSI_CHAN, and the NV device is NV_UNIT.

NW_CHAN:
.BLKW 1 ; Channel to NW
NV_UNIT:
.BLKL 1 ; NV unit number
IO_STATUS:
.BLKW 4 ; I/O status block
$QIOW_S - ; QIO and wait
IOSB = IO_STATUS,- ; I/O status block
CHAN = NW_CHAN,- ; channel to NW
FUNC = #IO$_DEACCESS,- ; function is clear call
P6 = NV_UNIT ; on NV terminal
BSBW IO_ERROR ; Check system service and IOSB

Return Status

Secondary Status Values

The secondary status values are found in the third word of the IOSB.

For OpenVMS VAX, if the first word of the IOSB contains SS$_NORMAL, the third word can contain one or more of the following:

If the first word of the IOSB contains SS$_ABORT or SS$_IVDEVNAM, the third word can contain one of the following:

If the first word of the IOSB contains any status value other than SS$_ NORMAL, SS$_ABORT, or SS$_IVDEVNAM, the contents of the third word are meaningless.

Purpose

$QIO(IO$_READVBLK) is used in programs to receive data transmitted from a remote DTE over the virtual circuit.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], p1,p2,[p3],[p4],[p5],[p6]

Arguments

Modifiers

Example

In the following example, IO$_READVBLK needs to know the address and the size of the buffer where it places incoming data. The address of the buffer is READBUF and the size is READBUFSIZ. The channel to the network device is NW_CHAN.

; Declaring the data:
NW_CHAN:
           .BLKW   1                ; Network channel
IO_STATUS:
           .BLKW   4                ; I/O status block
READBUF:
           .BLKB   200              ; Buffer
          READBUFSIZ = .-READBUF

; Using the System Service:
$QIOW_S -                       ; Issue QIO and wait
        CHAN = NW_CHAN,-        ; to NW
        FUNC = #IO$_READVBLK,-  ; Function is read
        IOSB = IO_STATUS        ; I/O status block
        P1 = READBUF,-          ; Buffer address
        P2 = #READBUFSIZE       ; and size

Return Status

Secondary Status Values

The secondary status values are found in the third word of the IOSB.

If the first word of the IOSB contains SS$_NORMAL, the third word can contain one or more of the following:

If the first word of the IOSB contains any other status value, the content of the third word is undefined.

Purpose

$QIO(IO$_WRITEVBLK) is used in programs to transmit data over a virtual circuit.

Note that if your last QIO transmitted data with the IO$M_MORE qualifier, you can use $QIO(IO$_WRITEVBLK) with a zero data packet to send the remaining data from the previous QIO. Otherwise, if you send a zero data packet, $QIO(IO$_WRITEVBLK) will complete with a success status, but no data will be sent.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], p1,p2 ,[p3],[p4],[p5],[p6]

Arguments

Modifiers

Example

In the following example, IO$_WRITEVBLK needs the address and the length of the data to be transmitted. Here, the address is in Register 2 (R2) and the length in Register 3 (R3). The channel to the network device is PSI_CHAN.

; Declaring the data:
PSI_CHAN:
           .BLKW   1               ; Channel
IO_STATUS:
           .BLKW   4               ; I/O status block
                                   ; Using the System Service:
$QIOW_S -                          ; Issue a QIO and wait
        CHAN = PSI_CHAN,-          ; to the network device
        FUNC = #IO$_WRITEVBLK,-    ; Function is write
        IOSB = IO_STATUS,-         ; I/O status block
        P1 = (R2),-                ; Buffer address
        P2 = R3                    ; and size

Return Status

Purpose

The QIO system service with a function code of IO$_NETCONTROL and a subfunction of PSI$K_INTACK confirms the receipt of an interrupt.

This service is only valid for X.25 calls. For X.29 calls, the NV device automatically acknowledges interrupts.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], [p1],[p2],[p3],p4,[p5],[p6]

Arguments

Example

In the following example, the subfunction of the system service call confirms the receipt of an interrupt—the subfunction is expressed in p4. The channel to the network device is INT_CHAN.

; Declaring the data:
INT_CHAN:
           .BLKW   1             ; Network channel
IO_STATUS:
           .BLKW   4             ; I/O status block
                                 ; Using the System Service:
$QIOW_S -                        ; Issue QIO and wait
        CHAN = INT_CHAN,-        ; to the network
        FUNC = #IO$_NETCONTROL,- ; Function is network
                                 ; control
        IOSB = IO_STATUS,-       ; I/O status block
        P4 = #PSI$K_INTACK       ; Subfunction is confirm
                                 ; interrupt received

Return Status

Purpose

The QIO system service with a function code of IO$_NETCONTROL and a subfunction of PSI$K_INTERRUPT sends an interrupt over the virtual circuit.

Only one interrupt in each direction can be in progress over a virtual circuit at any time. Once you have sent an interrupt, it is not possible to send another until the remote DTE confirms receipt of the first. This is indicated by completion of the IO$_NETCONTROL operation that you used to send the first interrupt.

Note that a single interrupt may be in progress in each direction. Thus, you may receive an interrupt, and possibly confirm receipt of this incoming interrupt while awaiting confirmation of an outgoing one.

This means that cooperating processes could deadlock if they do not allow asynchronous code to perform an acknowledgment whilst waiting for a synchronous IO$_NETCONTROL operation to complete.

This service is only valid for X.25 calls. In X.29 calls, the NV device automatically sends interrupts as required by the X.29 protocol.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], p1,p2,[p3],p4,[p5],[p6]

Arguments

Example

In the following example, the subfunction of the system service call transmits an interrupt—the subfunction is expressed in p4. The channel to the network device is INT_CHAN. The interrupt buffer is found at address INTBUF and its size is INTBUFSIZ.

; Declaring the data:
INT_CHAN:
           .BLKW   1             ; Network channel
IO_STATUS:
           .BLKW   4             ; I/O status block
INTBUF:
           .BLKB   10            ; Interrupt buffer
           INTBUFSIZ = .-INTBUF
; Using the System Service:
$QIOW_S -                        ; Issue QIO and wait
        CHAN = INT_CHAN,-        ; to the network
        FUNC = #IO$_NETCONTROL-  ; Function is network
                                 ; control
        IOSB = IO_STATUS,-       ; I/O status block
        P1 = INTBUF,-            ; Buffer address
        P2 = #INTBUFSIZ          ; and size
        P4 = #PSI$K_INTERRUPT    ; Subfunction is interrupt

Return Status

Purpose

The QIO system service with a function code of IO$_NETCONTROL and a subfunction of PSI$K_RESET resets a virtual circuit or confirms the receipt of a reset. The service resets a virtual circuit if no reset is outstanding, or confirms the receipt of a reset if one is outstanding. All pending messages are discarded if the virtual circuit is reset.

A return status of SS$_NORMAL does not guarantee that the remote DTE receives the diagnostic code. For example, the remote DTE may not receive the diagnostic code if a collision of resets occurs within the PSDN.

This service is only used for X.25 calls. In X.29 calls, the NV device automatically handles resets.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], [p1],[p2], [p3],p4,[p5],[p6]

Arguments

Example

Here, the subfunction of the system service call transmits a reset or confirms reception of a reset—the subfunction is expressed in p4. The channel to the network device is NW_CHAN. Because p3 is not specified, the diagnostic code defaults to 0.

; Declaring the data:
NW_CHAN:
           .BLKW   1             ; Network channel
IO_STATUS:
           .BLKW   4             ; I/O status block
; Using the System Service:
$QIOW_S -                        ; Issue QIO and wait
        CHAN = NW_CHAN,-         ; to NW
        FUNC = #IO$_NETCONTROL-  ; Function is network
                                 ; control
        IOSB = IO_STATUS,-       ; I/O status block
        P4 = #PSI$K_RESET        ; Subfunction is reset

Return Status

Purpose

The QIO system service with a function code of IO$_NETCONTROL and a subfunction of PSI$K_RESTART confirms the receipt of a restart on a PVC.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], [p1],[p2],[p3],p4,[p5],[p6]

Arguments

Example

The subfunction of the system service call confirms the receipt of a restart. The subfunction is named in p4. The channel to the network device is PVC_CHAN.

; Declaring the data:
PVC_CHAN:
           .BLKW   1              ; Network channel
IO_STATUS:
           .BLKW   4              ; I/O status block
; Using the System Service:
$QIOW_S -                         ; Issue QIO and wait
        CHAN = PVC_CHAN,-         ; to the circuit
        FUNC = #IO$_NETCONTROL,-  ; Function is network
                                  ; control
        IOSB = IO_STATUS,-        ; I/O status block
        P4 = #PSI$K_RESTART       ; Subfunction is restart

Return Status

Purpose

$QIO(IO$_NETCONTROL, PSI$K_X29_READ) is used in X.29 programs to read PAD parameters and NV terminal characteristics.

This QIO performs an operation equivalent to the DCL command SHOW TERMINAL/X29.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], p1,p2,p3,p4,[p5],p6

Arguments

Purpose

PSI$K_X29_BREAK_ACTION returns the NV Action Descriptor Block. The block contains details of the actions the NV device will take on receiving an Indication–of–break from the X.29 terminal.

The buffer size should be PSI$K_X29_ACTION_LENGTH (head = 20 bytes) to ensure the buffer is allocated sufficient space to hold the NV Action Descriptor Block that is returned.

Refer to the VSI X.25 for OpenVMS Programming Guide for a description of the NV Action Descriptor Block.

Example

NW_CHAN:
  .BLKW   1              ; Channel to NW
NV_UNIT:
  .BLKL   1              ; NV unit number
IO_STATUS:
  .BLKW   4              ;I/O Status block
DESC_BLOCK:
  .BLKB   PSI$K_X29_ACTION_LENGTH        ; Action Descriptor block
  $QIOW_S -                              ; Issue QIO and wait
    IOSB = IO_STATUS,-                   ; I/O Status block
    CHAN = NW_CHAN,-                     ; Control channel to NW
    FUNC = #IO$_NETCONTROL,-             ; Function is NETCONTROL
    P1 = DESC_BLOCK,-                    ; address of descriptor block
    P2 = #PSI$K_X29_ACTION_LENGTH,-      ; length of descriptor block
    P3 = #PSI$K_X29_BREAK_ACTION,-       ; Subfunction
    P4 = #PSI$K_X29_READ,-               ; read data
    P6 = NV_UNIT                         ; NV unit number
  BSBW IO_ERROR    ; check system service and IOSB

Return Status

Purpose

This subfunction reads the hangup PAD parameter template into a user–specified buffer.

The hangup PAD parameter template defines PAD characteristics after an X.29 call has been cleared.

A buffer size of 256 bytes is normally adequate. This allows for 32 parameters.

Refer to the VSI X.25 for OpenVMS Utilities Guide for a description of PAD parameter templates.

Example

NW_CHAN:
  .BLKW   1             ; Channel to NW
IO_STATUS:              ; I/O status block
  .BLKW   4
TEMPLATE_ENTRIES = 32   ; Allow for 32 parameters
TEMPLATE_BUFFER:        ; Buffer to manipulate
  .BLKB  TEMPLATE_ENTRIES * PSI$K_X29_PARAM_LENGTH
TEMPLATE_BUFFER_LEN = .-TEMPLATE_BUFFER    ; template
; Read the hangup PAD parameter template
;
;-
  $QIOW_S -                     ; Issue QIO and wait
    CHAN = NW_CHAN,-            ; to network device
    FUNC = #IO$_NETCONTROL,-    ; function is network control
    IOSB = IO_STATUS,-          ; I/O status block
    P1 = TEMPLATE_BUFFER,-      ; address of buffer
    P2 = #TEMPLATE_BUFFER_LEN,- ; length of buffer
    P3 = #PSI$K_X29_HANGUP_PARAMS,-
    -                           ; read subfunction specifies
    -                           ; which template to manipulate
    P4 = #PSI$K_X29_READ,-      ; NV read operation
    P6 = NV_UNIT                ; NV unit number
  BSBW IO_ERROR       ; Check for I/O error
;+

Return Status

Purpose

This parameter returns the value of the Hold Timer into the specified buffer.

The timer value is in units of 1/10 of a second.

The buffer size should be set to 4 bytes to ensure the buffer is allocated sufficient space to hold the timer value returned.

Example

NW_CHAN:
  .BLKW   1      ; Channel to NW
NV_UNIT:
  .BLKL   1      ; NV unit number
IO_STATUS:
  .BLKW   4      ; I/O status block
TIMER:
  .BLKB   4      ; Hold Timer buffer
         $QIOW_S -                             ; Issue QIO and wait
                 IOSB = IO_STATUS,-            ; I/O Status Block
                 CHAN = NW_CHAN,-              ; Control channel to NW
                 FUNC = #IO$_NETCONTROL,-      ;Function is NETCONTROL
                 P1   = TIMER                  ; Address of output
                                               ; buffer
                 P2   = #4                     ; Length of output
                                               ; buffer
                 P3   = #PSI$K_HOLD_TIMER,-    ; Subfunction
                 P4   = #PSI$K_X29_READ,-      ; Read data
                 P6   = NV_UNIT                ; NV Unit number
          BSBW   IO_ERROR                      ; Check system service
                                               ; and IOSB

Return Status

Purpose

This subfunction reads the host–echo PAD parameter template into a user– specified buffer.

The host–echo PAD parameter template defines characteristics of the PAD in host–echo mode.

A buffer size of 256 bytes is normally adequate. This allows for 32 PAD parameters.

PAD parameter templates are described in the VSI X.25 for OpenVMS Utilities Guide.

Example

NW_CHAN:
  .BLKW   1     ; Channel to NW
NV_UNIT:
  .BLKL 1       ; NV unit number
IO_STATUS:      ; I/O status block
  .BLKQ   1
TEMPLATE_ENTRIES = 32           ; Allow for 32 parameters

TEMPLATE_BUFFER:                ; Buffer to manipulate
  .BLKB  TEMPLATE_ENTRIES * PSI$K_X29_PARAM_LENGTH
TEMPLATE_BUFFER_LEN = .-TEMPLATE_BUFFER    ; template

; Read the Host-echo PAD parameter template
;
;-
  $QIOW_S -                     ; Issue QIO and wait
    CHAN = NW_CHAN,-            ; to network device
    FUNC = #IO$_NETCONTROL,-    ; function is network control
    IOSB = IO_STATUS,-          ; I/O status block
    P1 = TEMPLATE_BUFFER,-      ; address of buffer
    P2 = #TEMPLATE_BUFFER_LEN,- ; length of buffer
    P3 = #PSI$K_X29_HOST_ECHO_PARAMS,-
    -                           ; read subfunction specifies
    -                           ; which template to manipulate
    P4 = #PSI$K_X29_READ,-      ; NV read operation
    P6 = NV_UNIT                ; NV unit number
  BSBW IO_ERROR       ; Check for I/O error
;+

Return Status

Purpose

This parameter returns the NV Action Descriptor Block. This contains details of the actions the NV device will take on receiving an Interrupt message from the X.29 terminal.

The buffer size should be PSI$K_X29_ACTION_LENGTH (= 20 bytes) to ensure the buffer is allocated sufficient space to hold the NV Action Descriptor Block that is returned.

For a description of the NV Action Descriptor Block, refer to the VSI X.25 for OpenVMS Programming Guide.

Example

NW_CHAN:
  .BLKW   1      ; Channel to NW
NV_UNIT:
  .BLKL   1      ; NV unit number
IO_STATUS:
  .BLKW   4      ;I/O Status block
DESC_BLOCK:
  .BLKB   PSI$K_X29_ACTION_LENGTH  ; Action Descriptor block
         $QIOW_S -                        ; Issue QIO and wait
          IOSB = IO_STATUS,-              ; I/O Status block
          CHAN = NW_CHAN,-                ; Control channel to NW
          FUNC = #IO$_NETCONTROL,-        ; Function is NETCONTROL
          P1 = DESC_BLOCK,-               ; address of descriptor block
          P2 = #PSI$K_X29_ACTION_LENGTH,- ; length of descriptor block
          P3 = #PSI$K_X29_INT_ACTION,-    ; Subfunction
          P4 = #PSI$K_X29_READ,-          ; read data
          P6 = NV_UNIT                    ; NV unit number
         BSBW  IO_ERROR  ; check system service and IOSB

Return Status

Purpose

This subfunction reads the local–echo PAD parameter template into a user– specified buffer.

The local–echo PAD parameter template defines characteristics of the PAD in local–echo mode.

A buffer size of 256 bytes is normally adequate. This allows for 32 PAD parameters.

PAD parameter templates are described in the VSI X.25 for OpenVMS Utilities Guide.

Example

NW_CHAN:
  .BLKW   1 ; Channel to NW
NV_UNIT:
  .BLKL   1 ; NV unit number
IO_STATUS: ; I/O status block
  .BLKQ   1
TEMPLATE_ENTRIES = 32 ; Allow for 32 parameters
TEMPLATE_BUFFER:       ; Buffer to manipulate
  .BLKB TEMPLATE_ENTRIES * PSI$K_X29_PARAM_LENGTH
TEMPLATE_BUFFER_LEN = .-TEMPLATE_BUFFER ; template
; Read the Local-echo PAD parameter template
;
;-
$QIOW_S - ; Issue QIO and wait
CHAN = NW_CHAN,- ; to network device
FUNC = #IO$_NETCONTROL,- ; function is network control
IOSB = IO_STATUS,- ; I/O status block
P1 = TEMPLATE_BUFFER,- ; address of buffer
P2 = #TEMPLATE_BUFFER_LEN,- ; length of buffer
P3 = #PSI$K_X29_LOCAL_ECHO_PARAMS,-
- ; read subfunction specifies
- ; which template
P4 = #PSI$K_X29_READ,- ; NV read operation
P6 = NV_UNIT ; NV unit number
BSBW IO_ERROR ; Check for I/O error
;+

Return Status

Purpose

This subfunction returns the PAD Parameter List into the specified buffer.

The PAD Parameter List contains details of PAD parameters read. The actual length of the list is returned in the IOSB.

A buffer size of 512 is normally adequate. This allows for 64 PAD parameters.

Refer to the VSI X.25 for OpenVMS Programming Guide for a description of the PAD Parameter List. Refer to Appendix E, Standard PAD Parameters for a complete description of the PAD parameters.

The following example and Figure 4.1, “$QIO(IO$_NETCONTROL!PSI$K_X29_READ) Operations” show:

Example

NW_CHAN:
  .BLKW   1     ; Channel to NW
NV_UNIT:
  .BLKL   1     ; NV unit number
IO_STATUS:
  .BLKW   4     ;I/O Status block
PARAM_ENTRIES = 64      ; Allow for 64 parameters
PARAM_BUFFER:           ; Buffer to manipulate parameters
  .BLKB   PARAM_ENTRIES * PSI$K_X29_PARAM_LENGTH
PARAM_BUFFER_LEN = .-PARAM_BUFFER
  $QIOW_S -                     ; Issue QIO and wait
    IOSB = IO_STATUS,-          ; I/O Status block
    CHAN = NW_CHAN,-            ; Control channel to NW
    FUNC = #IO$_NETCONTROL,-    ; Function is NETCONTROL
    P1 = PARAM_BUFFER,-         ; address of Parameter List
    P2 = PARAM_BUFFER_LEN,-     ; length of Parameter List
    P3 = #PSI$K_X29_PAD_PARAMS  ; Subfunction
    P4 = #PSI$K_X29_READ,-      ;read data
    P6 = NV_UNIT                ; NV unit number
  BSBW  IO_ERROR   ; check system service and IOSB

Return Status

Purpose

This returns the setting of the TEMP_NOHANG flag into the buffer supplied.

Only bit 0 is used. If PSI$K_X29_TEMP_NOHANG is set, the virtual circuit will not be cleared on a subsequent $DASSGN call.

The buffer size should be 4 to ensure the buffer is allocated sufficient space to hold the value returned.

Example

NW_CHAN:
  .BLKW  1      ; Channel to NW
TEMP_NOHANG_ON:
  .BLKL  1      ; Value of temp nohang
NV_UNIT:
  .BLKL  1      ; NV unit number
IO_STATUS:
       .BLKW  4 ; I/O Status block
;+
; Read the temp_nohang bit
;-
  $QIOW_S  -                    ; QIO and wait
    IOSB = IO_STATUS,-          ; I/O status block
    CHAN = NW_CHAN,-            ; channel to NW
    FUNC = #IO$_NETCONTROL,-    ; function is net control
    P1 = TEMP_NOHANG_ON,-       ; output buffer
    P2 = #4,-                   ; longword
    P3 = #PSI$K_X29_TEMP_NOHANG,-; subfunction
    P4 = #PSI$K_X29_READ,-      ; NV read operation
    P6 = NV_UNIT                ; NV unit number
  BSBW IO_ERROR         ; Check system service and IOSB

Return Status

Purpose

$QIO(IO$_NETCONTROL, PSI$K_X29_READ_SPECIFIC) is used in X.29 programs to read specific PAD parameters.

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], p1,p2,p3,p4,[p5],p6

Arguments

Purpose

This subfunction returns specific PAD parameters into the specified buffer.

The buffer described by p1 and p2 is read to get a list of the parameters that should be returned. NV issues an X.29 read parameters message to the PAD, requesting the parameters listed in the buffer.

On completion of the QIO, the buffer is overwritten with the parameters returned from the PAD.

For a description of the PAD Parameter List, refer to the VSI X.25 for OpenVMS Programming Guide. For a complete description of the PAD parameters, refer to Appendix E, Standard PAD Parameters.

Figure 4.2, “$QIO(IO$_NETCONTROL!PSI$K_X29_READ_SPECIFIC) Operations” shows:

Example

In this example, QIO(IO$_NETCONTROL) is used to read the parameters specified in PARAM_BUFFER (ECHO and network–specific parameter 42).

.MACRO  PAD_PARAM_ITEM  CODE, VALUE=0, ATTR=0
  .WORD  CODE           ; PSI$W_X29_PARAM_REF
  .WORD  ATTR           ; PSI$W_X29_PARAM_FLAGS
  .BYTE  VALUE          ; PSI$B_X29_PARAM_VALUE
  .BYTE  0, 0, 0        ; Must be zero
.ENDM
NW_CHAN:
  .BLKW  1              ; Channel to NW
NV_UNIT:
  .BLKL  1              ; NV unit number
IO_STATUS:              ; I/O status block
  .BLKW  4
PARAM_BUFFER:
ECHO:  PAD_PARAM_ITEM   ; find out the echo setting
    CODE=PSI$K_X29_PAR_ECHO
  PAD_PARAM_ITEM        ; Network specific parameters follow
    CODE=0, VALUE=0
PAR42:  PAD_PARAM_ITEM  ; find network specific parameter 42
    CODE=42
PARAM_BUFFER_LEN = .-PARAM_BUFFER ;

;
; Get the PAD parameters
;-
  $QIOW_S -                             ; Issue QIO and wait
    CHAN = NW_CHAN,-                    ; to network device
    FUNC = #IO$_NETCONTROL,-            ; Function is network control
    IOSB = IO_STATUS,-                  ; I/O status block
    P1 = PARAM_BUFFER,-                 ; Address of buffer
    P2 = PARAM_BUFFER_LEN,-             ; Length of buffer
    P3 = #PSI$K_X29_PAD_PARAMS,-        ; Subfunction specifies
    -                                   ; read PAD parameters
    P4 = #PSI$K_X29_READ_SPECIFIC,-     ; NV read specific operation
    P6 = NV_UNIT                        ; NV unit number
  BSBW  IO_ERROR      ; Check for I/O error

Return Status

Purpose

$QIO(IO$_NETCONTROL, PSI$K_X29_SET) is used in X.29 programs to set PAD parameters and NV terminal characteristics.

This QIO performs an operation equivalent to the DCL command SET TERMINAL/X29.

Figure 4–3 shows:

Format

$QIO [efn],chan,func,[iosb],[astadr],[astprm], p1,p2,p3,p4,[p5],p6

Arguments

Purpose

This parameter defines the action, or series of actions, that NV is to take when an Indication–of–break X.29 message is received.

Usually, PSI$K_X29_BREAK_ACTION is specified for when you issue a BREAK command while using the host–based PAD.

Parameter p2 specifies the size of the NV Action Descriptor Block. Set p2 either to PSI$K_X29_ACTION_LENGTH (= 20 bytes), or to a value between 4 and 20 bytes.

Set one or more of the following bits in the 4–byte Action flag (byte 0 to 3):

Only the first three bits of byte 0 are used.

If you require other actions to be taken, set the counted string PSI$T_X29_ ACTION_STRING in the NV Action Descriptor Block.

For details of the NV Action Descriptor Block, refer to the VSI X.25 for OpenVMS Programming Guide.

Example

NW_CHAN:
  .BLKW  1      ; Channel to NW
NV_UNIT:
  .BLKL  1      ; NV Unit number
IO_STATUS:
  .BLKW  4      ; I/O Status block
DESC_BLOCK:
  .LONG  PSI$M_X29_ACTION_PURGE!- ;Descriptor block
    PSI$M_X29_ACTION_RESET
;
STRING:
  .BYTE  STRING_LENGTH-1      ;Count
  .BYTE  24                   ;^X
  .BYTE  15                   ;^0
  STRING_LENGTH = .-STRING
  DESC_LENGTH   = .-DESC_BLOCK
;
  $QIOW_S -                   ; Issue QIO and wait
  IOSB = IO_STATUS            ; I/O Status block
  CHAN = NW_CHAN,-            ;Control channel to NW
  FUNC = #IO$_NETCONTROL,-    ;Function is NETCONTROL
  P1 = DESC_BLOCK,-           ;Address of descriptor block
  P2 = #DESC_LENGTH,-         ;Length of descriptor block
  P3 = #PSI$K_X29_BREAK_ACTION,- ;Subfunction
  P4 = #PSI$K_X29_SET,-       ;NV set data
  P6 = NV_UNIT                ;NV Unit number
;
  BSBW  IO_ERROR    ;Check system service and IOSB

Return Status

Purpose

This subfunction sets the hangup PAD parameter template.

The hangup PAD parameter template defines the PAD characteristics after an X.29 call has been cleared.

Parameter p2 is the size of the PAD parameter buffer. Calculate p2 as follows:

(number of PAD parameters to be set) * PSI$K_X29_PARAM_LENGTH

Refer to the VSI X.25 for OpenVMS Utilities Guide for a description of how to use PAD parameter templates.

Example

This example sets the hangup PAD parameter template to turn on echo and editing.

.MACRO  PAD_PARAM_ITEM  CODE, VALUE=0, ATTR=0
  .WORD  CODE           ; PSI$W_X29_PARAM_REF
  .WORD  ATTR           ; PSI$W_X29_PARAM_FLAGS
  .BYTE  VALUE          ; PSI$B_X29_PARAM_VALUE
  .BYTE  0, 0, 0        ; Must be zero
.ENDM
NW_CHAN:
  .BLKW  1              ; Channel to NW
IO_STATUS:              ; I/O status block
  .BLKQ  1
TEMPLATE_BUFFER:
  PAD_PARAM_ITEM  -      ; Turn on Echo
    CODE=PSI$K_X29_PAR_ECHO, VALUE=1
  PAD_PARAM_ITEM  -      ; Turn on Editing
    CODE=PSI$K_X29_PAR_EDIT, VALUE=1
TEMPLATE_BUFFER_LEN = .-TEMPLATE_BUFFER   ; template
;
; Set the PAD parameter template
;-
  $QIOW_S -                     ; Issue QIO and wait
    CHAN = NW_CHAN,-            ; to network device
    FUNC = #IO$_NETCONTROL,-    ; Function is net control
    IOSB = IO_STATUS,-          ; I/O status block
    P1 = TEMPLATE_BUFFER,-      ; Address of buffer
    P2 = TEMPLATE_BUFFER_LEN,-  ; Length of buffer
    P3 = #PSI$K_X29_HANGUP_PARAMS,-
    -           ; Subfunction specifies
    -           ; which template to manipulate
    P4 = #PSI$K_X29_SET,-       ; NV set operation
    P6 = NV_UNIT                ; NV unit number
  BSBW  IO_ERROR      ; Check for I/O error

Return Status

Purpose

This subfunction sets the host–echo PAD parameter template.

The host–echo PAD parameter template defines characteristics of the PAD in host–echo mode.

Parameter p2 is the size of the PAD parameter buffer. Calculate p2 as follows:

(number of PAD parameters to be set ) * PSI$K_X29_PARAM_LENGTH

Refer to the VSI X.25 for OpenVMS Utilities Guide for a description of how to use PAD parameter templates.

If the NV device is in host–echo mode, the NV device will consult the new template, and configure the PAD according to the instructions in the template.

Example

This example sets the host–echo PAD parameter template so that echo and editing are turned off, the user’s timeout value is used, and wrap and newline are turned off.

.MACRO  PAD_PARAM_ITEM  CODE, VALUE=0, ATTR=0
  .WORD  CODE           ; PSI$W_X29_PARAM_REF
  .WORD  ATTR           ; PSI$W_X29_PARAM_FLAGS
  .BYTE  VALUE          ; PSI$B_X29_PARAM_VALUE
  .BYTE  0, 0, 0        ; Must be zero
.ENDM
NW_CHAN:
  .BLKW  1              ; Channel to NW
IO_STATUS:              ; I/O status block
  .BLKQ  1
NV_UNIT:
  .BLKL  1              ; NV unit number
TEMPLATE_BUFFER:
  PAD_PARAM_ITEM  -     ; Turn Echo off
    CODE=PSI$K_X29_PAR_ECHO, VALUE=0
  PAD_PARAM_ITEM  -     ; Turn Editing off
    CODE=PSI$K_X29_PAR_EDIT, VALUE=0
  PAD_PARAM_ITEM  -     ; Use the user’s timeout value
    CODE=PSI$K_X29_PAR_TIMEOUT, ATTR=PSI$M_X29_USER_VALUE
  PAD_PARAM_ITEM  -     ; Turn off wrap
    CODE=PSI$K_X29_PAR_WRAP, VALUE=0
  PAD_PARAM_ITEM  -     ; Turn off Newline
    CODE=PSI$K_X29_PAR_NEW_LINE, VALUE=0
TEMPLATE_BUFFER_LEN = .-TEMPLATE_BUFFER   ; template
;
; Set the PAD parameter template
;-
  $QIOW_S -                     ; Issue QIO and wait
    CHAN = NW_CHAN,-            ; to network device
    FUNC = #IO$_NETCONTROL,-    ; Function is net control
    IOSB = IO_STATUS,-          ; I/O status block
    P1 = TEMPLATE_BUFFER,-      ; Address of buffer
    P2 = TEMPLATE_BUFFER_LEN,-  ; Length of buffer
    P3 = #PSI$K_X29_HOST_ECHO_PARAMS,-
    -           ; Subfunction specifies
    -           ; which template to manipulate
    P4 = #PSI$K_X29_SET,-       ; NV set operation
    P6 = NV_UNIT                ; NV unit number
  BSBW  IO_ERROR      ; Check for I/O error

Return Status

Purpose

This parameter sets the Hold Timer to units of 1/10 of a second.

Parameter p2 is the size of the buffer that stores the timer value. Set p2 to 4 bytes.

Set the timer to 0 to transmit all output from NV to the X.29 terminal immediately.

For details of how the Hold Timer functions in relation to the NV device, refer to the VSI X.25 for OpenVMS Programming Guide.

Example

In this example the Hold Timer is set to 1/5 second.

NW_CHAN:
  .BLKW  1      ; Channel to NW
NV_UNIT:
  .BLKL  1      ; NV Unit number
IO_STATUS:
  .BLKW  4      ; I/O Status block
HOLD_TIMER:
  .LONG  2      ;Hold timer value
;
  $QIOW_S -                             ; Issue QIO and wait
  IOSB = IO_STATUS                      ; I/O Status block
  CHAN = NW_CHAN,-                      ;Control channel to NW
  FUNC = #IO$_NETCONTROL,-              ;Function is NETCONTROL
  P1   = HOLD_TIMER                     ;New hold timer
  P2   = #4                             ;Longword
  P3   = #PSI$K_X29_HOLD_TIMER,-        ;Subfunction
  P4   = #PSI$K_X29_SET,-               ;NV set data
  P6   = NV_UNIT                        ;NV Unit number
;
   BSBW  IO_ERROR        ;Check system service and IOSB

Return Status

Purpose

This parameter sets the actions to be taken when an interrupt issued at the X.29 terminal is received as an X.25 Interrupt.

Parameter p2 is the size of the NV Action Descriptor Block. Set p2 either to PSI$K_X29_ACTION_LENGTH (= 20 bytes), or to a value between 4 and 20 bytes.

Set one or more of the following bits in the 4–byte Action flag (byte 0 to 3):

Only the first three bits of byte 0 are used.

If you require other actions to be taken, set the counted string (PSI$T_X29_ ACTION_STRING) in the NV Action Descriptor Block.

For details of the NV Action Descriptor Block, refer to the VSI X.25 for OpenVMS Programming Guide.

Example

In the following example, the Typeahead buffer is purged automatically and the NV input is purged by setting PSI$V_X29_ACTION_PURGE in the Action flag Ctrl/Y and in the counted string.

NW_CHAN:
  .BLKW  1      ; Channel to NW
NV_UNIT:
  .BLKL  1      ; NV Unit number
IO_STATUS:
  .BLKW  4      ; I/O Status block
DESC_BLOCK:     ;Descriptor block
  .LONG  PSI$M_X29_ACTION_PURGE  ;Purge NV
;
STRING:
  .BYTE  STRING_LENGTH  ;Count
  .BYTE  25             ;^Y
  STRING_LENGTH = .-STRING
  DESC_LENGTH   = .-DESC_BLOCK
;
  $QIOW_S -                             ; Issue QIO and wait
  IOSB = IO_STATUS                      ; I/O Status block
  CHAN = NW_CHAN,-                      ;Control channel to NW
  FUNC = #IO$_NETCONTROL,-              ;Function is NETCONTROL
  P1   = DESC_BLOCK,-                   ;Address of descriptor block
  P2   = #DESC_LENGTH,-                 ;Length of descriptor block
  P3   = #PSI$K_X29_INT_ACTION,-        ;Subfunction
  P4   = #PSI$K_X29_SET,-               ;NV set data
  P6   = NV_UNIT                        ;NV Unit number
;
   BSBW IO_ERROR     ;Check system service and IOSB

Return Status

Purpose

This subfunction sets the local–echo PAD parameter template.

The local–echo PAD parameter template defines characteristics of the PAD in local–echo mode.

Parameter p2 is the size of the PAD parameter buffer. Calculate p2 as follows: (number of PAD parameters to be set) * PSI$K_X29_PARAM_LENGTH

Refer to the VSI X.25 for OpenVMS Utilities Guide for a description of how to use PAD parameter templates.

Example

.MACRO  PAD_PARAM_ITEM  CODE, VALUE=0, ATTR=0
  .WORD  CODE           ; PSI$W_X29_PARAM_REF
  .WORD  ATTR           ; PSI$W_X29_PARAM_FLAGS
  .BYTE  VALUE          ; PSI$B_X29_PARAM_VALUE
  .BYTE  0, 0, 0        ; Must be zero
.ENDM
NW_CHAN:
  .BLKW  1      ; Channel to NW
NV_UNIT:
  .BLKL  1      ; NV unit number
IO_STATUS:      ; I/O status block
  .BLKW  4
TEMPLATE_BUFFER:
  PAD_PARAM_ITEM  -  ; Calculate echo
    CODE=PSI$K_X29_PAR_ECHO, ATTR=PSI$M_X29_CALCULATE
  PAD_PARAM_ITEM  -  ; Turn Editing on
    CODE=PSI$K_X29_PAR_EDIT, VALUE=1
  PAD_PARAM_ITEM  -  ; Turn off timeouts
    CODE=PSI$K_X29_PAR_TIMEOUT, VALUE=0
  PAD_PARAM_ITEM  -  ; Set up newline
    CODE=PSI$K_X29_PAR_NEW_LINE, VALUE=4
TEMPLATE_BUFFER_LEN = .-TEMPLATE_BUFFER   ; template
;
; Set the PAD parameter template
;-
  $QIOW_S -                             ; Issue QIO and wait
    CHAN = NW_CHAN,-                    ; to network device
    FUNC = #IO$_NETCONTROL,-            ; Function is network control
    IOSB = IO_STATUS,-                  ; I/O status block
    P1 = TEMPLATE_BUFFER,-              ; Address of buffer
    P2 = TEMPLATE_BUFFER_LEN,-          ; Length of buffer
    P3 = #PSI$K_X29_LOCAL_ECHO_PARAMS,-
    -        ; Subfunction specifies
    -        ; which template to manipulate
    P4 = #PSI$K_X29_SET,-               ; NV set operation
    P6 = NV_UNIT                        ; NV unit number
  BSBW IO_ERROR                  ; Check for I/O error

Return Status

Purpose

This parameter assigns values to specified PAD parameters.

Parameter p2 is the size of the PAD Parameter List. Calculate p2 as follows:

(number of PAD parameters to be set) * PSI$K_X29_PARAM_LENGTH

The PAD Parameter List consists of PAD parameter items. To set standard PAD parameters, you should specify the appropriate Parameter Code in the type field, followed by the required value.

Refer to Appendix E, Standard PAD Parameters for details of the PAD parameters, and refer to the VSI X.25 for OpenVMS Programming Guide for details of the PAD Parameter List and how PAD parameter settings may affect NV operation.

To set nonstandard PAD parameters, specify a sequence of items in the PAD Parameter List, as follows:

. . . and so on.

For details of the nonstandard PAD facilities that are supported, refer to the technical documentation supplied by the PSDN.

Example

The following code turns echo off by setting ECHO to zero.

.MACRO  PAD_PARAM_ITEM  CODE, VALUE=0, ATTR=0
  .WORD  CODE           ; PSI$W_X29_PARAM_REF
  .WORD  ATTR           ; PSI$W_X29_PARAM_FLAGS
  .BYTE  VALUE          ; PSI$B_X29_PARAM_VALUE
  .BYTE  0, 0, 0        ; Must be zero
.ENDM
NW_CHAN:
  .BLKW  1      ; Channel to NW
NV_UNIT:
  .BLKL  1      ; NV Unit number
IO_STATUS:
  .BLKW  4      ;I/O status block
PAD_PARAM_BLOCK:
  PAD_PARAM_ITEM  -  ; Turn Echo off
    CODE=PSI$K_X29_PAR_ECHO, VALUE=0
PAD_PARAM_LEN = .-PAD_PARAM_BLOCK
;+
; Make sure that the PAD echo parameter is turned off
;-
  $QIOW_S -                     ; QIO and wait
    CHAN = NW_CHAN,-            ; NW channel
    IOSB = IO_STATUS,-          ; I/O status block
    FUNC = #IO$_NETCONTROL,-    ; network control operation
    P1 = PAD_PARAM_BLOCK,-      ; PAD Parameter List
    P2 = #PAD_PARAM_LEN,-       ; length of block
    P3 = #PSI$K_X29_PAD_PARAMS,-; change PAD parameter
    P4 = #PSI$K_X29_SET,-       ; NV set operation
    P6 = NV_UNIT                ; NV unit number
  BSBW  IO_ERROR                ; Check system service and IOSB

Return Status

Secondary Return Status

Secondary status values are found in the third word of the IOSB.

If the first word of the IOSB contains SS$_BADPARAM, the third word will contain the PAD parameter number (IOSB word 4 contains the original value).

If the first word of the IOSB contains SS$_CTRLERR, contents of the third word will be:

Byte 1: X.29 error type

Byte 2: Invalid code

Purpose

This subfunction sends a PAD reselection message to the remote PAD.

The NCB item–list contains the parameters to put in the reselection message, remote DTE address, user data field and facilities.

Parameter p1 is the address of the start of the NCB item–list. Parameter p2 is the length of the NCB item–list.

NCB Contents

Only mandatory, optional, and ignore items are listed in the following table. Other items will generate an error if you use them.

Example

The following example sends a PAD reselection message to the remote PAD, with DTE address 234273400321, with optional user data and local PSDN facilities.

.MACRO  NCB_ITEM_HEADER   CODE, LENGTH=0
  .WORD  4+(LENGTH)
  .WORD  CODE
.ENDM
NW_CHAN:
  .BLKW  1              ; Channel to NW
IO_STATUS:              ; I/O status block
  .BLKQ  1
RESELECT_ITEM_LIST:
  NCB_ITEM_HEADER  psi$c_ncb_reselect_dte, 4+13
  .ascic "234273400321"
  NCB_ITEM_HEADER  psi$c_ncb_user_data, 4+7
  .ascic "BARRY"
  NCB_ITEM_HEADER  psi$c_ncb_locfac, 4+7
  .byte 6                 ; number of facility bytes
  .byte ^x43, ^x07, ^x07  ; Window size of 7
  .byte ^x42, ^x0a, ^x0a  ; Packet size of 1024
RESELECT_ITEM_LIST_LEN = .-RESELECT_ITEM_LIST
;
; Set the PAD parameter template
;-
  $QIOW_S -                             ; Issue QIO and wait
    CHAN = NW_CHAN,-                    ; to network device
    FUNC = #IO$_NETCONTROL,-            ; Function is net control
    IOSB = IO_STATUS,-                  ; I/O status block
    P1 = RESELECT_ITEM_LIST,-           ; Address of buffer
    P2 = RESELECT_ITEM_LIST_LEN,-       ; Length of buffer
    P3 = #PSI$K_X29_PAD_RESELECTION,-
    -      ; Subfunction specifies
    -      ; send pad reselection message
    P4 = #PSI$K_X29_SET,-               ; NV set operation
    P6 = NV_UNIT                        ; NV unit number
  BSBW  IO_ERROR       ; Check for I/O error

Return Status

Purpose

This parameter sets the X.29 terminal to enable TEMP_NOHANG.

Normally, when the last channel is deassigned from an NV unit, the call is cleared and all resources used by the unit are returned to the system. This subfunction temporarily disables terminal hangup and allows the NV unit to be passed to another process. Refer to the VIS X.25 for OpenVMS Programming Guide for further details.

When the channel has been deassigned and the login sequence has started, setting the TEMP_NOHANG flag to 0 does not affect operations.

Set p3 either to 1 (enable TEMP_NOHANG) or to 0 (disable TEMP_NOHANG). Set p2 (buffer length) to 4 bytes.

Example

The following code enables TEMP_NOHANG.

NW_CHAN:
  .BLKW  1      ; Channel to NW
TEMP_NOHANG_ON:
  .LONG  1      ; Value to set in temp no hang
NV_UNIT:
  .BLKL  1      ; NV unit number
IO_STATUS:
  .BLKW  4      ; I/O status block
;+
; Set the temp_nohang bit
;-
  $QIOW_S -                     ; QIO and wait
    IOSB = IO_STATUS,-          ; I/O status block
    CHAN = NW_CHAN,-            ; channel to NW
    FUNC = #IO$_NETCONTROL,-    ; function is net control
    P1 = TEMP_NOHANG_ON,-       ; value to set
    P2 = #4,-                   ; longword
    P3 = #PSI$K_X29_TEMP_NOHANG,-; change NV temp_nohang
    P4 = #PSI$K_X29_SET,-       ; NV set operation
    P6 = NV_UNIT                ; NV unit number
  BSBW  IO_ERROR                ; Check system service and IOSB

Return Status