Common Structure of LUA VCBs

The following data structure shows the parameters that are common to all Windows LUA verbs.

struct LUA_COMMON {
    unsigned short lua_verb;
    unsigned short lua_verb_length;
    unsigned short lua_prim_rc;
    unsigned long  lua_sec_rc;
    unsigned short lua_opcode;
    unsigned long  lua_correlator;
    unsigned char  lua_luname[8];
    unsigned short lua_extension_list_offset;
    unsigned short lua_cobol_offset;
    unsigned long  lua_sid;
    unsigned short lua_max_length;
    unsigned short lua_data_length;
    char FAR *     lua_data_ptr;
    unsigned long  lua_post_handle;
    struct LUA_TH  lua_th;
    struct LUA_RH  lua_rh;
    struct LUA_FLAG1 lua_flag1;
    unsigned char  lua_message_type;
    struct LUA_FLAG2 lua_flag2;
    unsigned char  lua_resv56[7];
    unsigned char  lua_encr_decr_option;
} LUA_COMMON;

Members

lua_verb

Supplied parameter. Contains the verb code, LUA_VERB_RUI for RUI verbs or LUA_VERB_SLI for SLI verbs. For both of these macros the value is 0x5200.

lua_verb_length

Supplied parameter. Specifies the length in bytes of the LUA VCB. It must contain the length of the verb record being issued.

lua_prim_rc

Primary return code set by LUA at the completion of the verb. The valid return codes vary depending on the LUA verb issued.

lua_sec_rc

Secondary return code set by LUA at the completion of the verb. The valid return codes vary depending on the LUA verb issued.

lua_opcode

Supplied parameter. Contains the LUA command code (verb operation code) for the verb to be issued, for example, LUA_OPCODE_RUI_BID for the RUI_BID verb. Valid values are as follows:

LUA_OPCODE_SLI_OPEN

LUA_OPCODE_SLI_CLOSE

LUA_OPCODE_SLI_RECEIVE

LUA_OPCODE_SLI_SEND

LUA_OPCODE_SLI_PURGE

LUA_OPCODE_SLI_BID

LUA_OPCODE_SLI_BIND_ROUTINE

LUA_OPCODE_SLI_STSN_ROUTINE

LUA_OPCODE_SLI_CRV_ROUTINE

LUA_OPCODE_RUI_INIT

LUA_OPCODE_RUI_TERM

LUA_OPCODE_RUI_READ

LUA_OPCODE_RUI_WRITE

LUA_OPCODE_RUI_PURGE

LUA_OPCODE_RUI_BID

lua_correlator

Supplied parameter. Contains a user-supplied value that links the verb with other user-supplied information. LUA does not use or change this information. This parameter is optional.

lua_luname

Supplied parameter. Specifies the ASCII name of the local LU used by the Windows LUA session.

SLI_OPEN and RUI_INIT require this parameter. Other Windows LUA verbs only require this parameter if lua_sid is zero.

This parameter is eight bytes long, padded on the right with spaces (0x20) if the name is shorter than eight characters.

lua_extension_list_offset

Specifies the offset from the start of the VCB to the extension list of user-supplied dynamic-link libraries (DLLs). This parameter is not used by RUI in Microsoft® SNA Server and should be set to zero. The value must be the beginning of a word boundary unless there is no extension list.

lua_cobol_offset

Offset of the Cobol extension. Not used by LUA in SNA Server and should be zero.

lua_sid

Supplied and returned parameter. Specifies the session identifier and is returned by SLI_OPEN and RUI_INIT. Other verbs use this parameter to identify the session used for the command. If other verbs use the lua_luname parameter to identify sessions, set the lua_sid parameter to zero.

lua_max_length

Specifies the length of received buffer for RUI_READ and SLI_RECEIVE. For other RUI and SLI verbs, it is not used and should be set to zero.

lua_data_length

Specifies the length of the data being sent or received. It specifies the length of data returned in lua_peek_data for the RUI_BID verb.

lua_data_ptr

Pointer to an application-supplied buffer.

When SLI_RECEIVE or RUI_READ is issued, this parameter points to the location to receive the data from the host.

When SLI_SEND or RUI_WRITE is issued, this parameter points to the location of the application's data to be sent to the host.

When SLI_PURGE or RUI_PURGE is issued, this parameter points to the location of the SLI_RECEIVE or RUI_READ verb's VCB that is to be canceled.

When SLI_OPEN is issued, this parameter can be one of the following:

The logon message for the SSCP normal flow when the initialization type is secondary with an unformatted logon message.
The RU for INITSELF. When the initialization type is secondary with INITSELF, the necessary data for the application is provided.
For all other open types, this field should be set to zero.

For other RUI and SLI verbs, this parameter is not used and should be set to zero. Both SNA commands and data are placed in this buffer and they can be in an EBCDIC format.

This information is provided by the Windows LUA application.

lua_post_handle

Supplied parameter. Used under Microsoft® Windows NT® and Microsoft® Windows® 95 if asynchronous notification is to be accomplished by events. This variable contains the handle of the event to be signaled or a window handle.

For all other environments, this parameter is reserved and should be set to zero.

lua_th

Returned parameter. Contains the SNA transmission header (TH) of the message sent or received. Various subparameters are set for write functions and returned for read and bid functions. The subparameters are as follows:

lua_th.flags_fid: Format identification type 2, four bits.
lua_th.flags_mpf: Segmenting mapping field, two bits. Defines the type of data segment. The following values are valid:
0x00Middle segment
0x04Last segment
0x08First segment
0x0COnly segment
lua_th.flags_odai: Originating address field–destination address field (OAF–DAF) assignor indicator, one bit.
lua_th.flags_efi: Expedited flow indicator, one bit.
lua_th.daf: Destination address field (DAF), an unsigned char.
lua_th.oaf: Originating address field (OAF), an unsigned char.
lua_th.snf: Sequence number field, an unsigned char[2].

lua_rh

Returned parameter. Contains the SNA request/response header (RH) of the message sent or received. It is set for the write function and returned by the read and bid functions. Its subparameters are as follows:

lua_rh.rri: Request-response indicator, one bit.
lua_rh.ruc: RU category, two bits. The following values are valid:
LUA_RH_FMD (0x00)FM data segment
LUA_RH_NC (0x20)Network control
LUA_RH_DFC (0x40)Data flow control
LUA_RH_SC (0x60)Session control
lua_rh.fi: Format indicator, one bit.
lua_rh.sdi: Sense data included indicator, one bit.
lua_rh.bci: Begin chain indicator, one bit.
lua_rh.eci: End chain indicator, one bit.
lua_rh.dr1i: Definite response 1 indicator, one bit.
lua_rh.dr2i: Definite response 2 indicator, one bit.
lua_rh.ri: Exception response indicator (for a request), or response type indicator (for a response), one bit.
lua_rh.qri: Queued response indicator, one bit.
lua_rh.pi: Pacing indicator, one bit.
lua_rh.bbi: Begin bracket indicator, one bit.
lua_rh.ebi: End bracket indicator, one bit.
lua_rh.cdi: Change direction indicator, one bit.
lua_rh.csi: Code selection indicator, one bit.
lua_rh.edi: Enciphered data indicator, one bit.
lua_rh.pdi: Padded data indicator, one bit.

lua_flag1

Supplied parameter. Contains a data structure containing flags for messages supplied by the application. This parameter is used by RUI_BID, RUI_READ, RUI_WRITE, SLI_BID, SLI_RECEIVE, and SLI_SEND. For other LUA verbs this parameter is not used and should be set to zero. Its subparameters are as follows:

lua_flag1.bid_enable: Bid enable indicator, one bit.
lua_flag1.close_abend: Close immediate indicator, one bit.
lua_flag1.nowait: No wait for data flag, one bit.
lua_flag1.sscp_exp: SSCP expedited flow, one bit.
lua_flag1.sscp_norm: SSCP normal flow, one bit.
lua_flag1.lu_exp: LU expedited flow, one bit.
lua_flag1.lu_norm: LU normal flow, one bit.

lua_message_type

Specifies the type of the inbound or outbound SNA commands and data. This is a returned parameter for RUI_INIT and SLI_OPEN and a supplied parameter for SLI_SEND. For other LUA verbs this variable is not used and should be set to zero.

Possible values are:

LUA_MESSAGE_TYPE_LU_DATA

LUA_MESSAGE_TYPE_SSCP_DATA

LUA_MESSAGE_TYPE_BID

LUA_MESSAGE_TYPE_BIND

LUA_MESSAGE_TYPE_BIS

LUA_MESSAGE_TYPE_CANCEL

LUA_MESSAGE_TYPE_CHASE

LUA_MESSAGE_TYPE_CLEAR

LUA_MESSAGE_TYPE_CRV

LUA_MESSAGE_TYPE_LUSTAT_LU

LUA_MESSAGE_TYPE_LUSTAT_SSCP

LUA_MESSAGE_TYPE_QC

LUA_MESSAGE_TYPE_QEC

LUA_MESSAGE_TYPE_RELQ

LUA_MESSAGE_TYPE_RQR

LUA_MESSAGE_TYPE_RTR

LUA_MESSAGE_TYPE_SBI

LUA_MESSAGE_TYPE_SHUTD

LUA_MESSAGE_TYPE_SIGNAL

LUA_MESSAGE_TYPE_SDT

LUA_MESSAGE_TYPE_STSN

LUA_MESSAGE_TYPE_UNBIND

The SLI receives and responds to the bind, crv, and stsn requests through the LUA interface extension routines.

lu_data, lustat_lu, lustat_sscp, and sscp_data are not SNA commands.

lua_flag2

Returned parameter. Contains flags for messages returned by LUA. This parameter is returned by RUI_BID, RUI_READ, RUI_WRITE, SLI_BID, SLI_RECEIVE, and SLI_SEND. For other LUA verbs this parameter is not used and should be set to zero. Its subparameters are as follows:

lua_flag2.bid_enable: Indicates that RUI_BID was successfully re-enabled if set to 1.
lua_flag2.async: Indicates that the LUA interface verb completed asynchronously if set to 1.
lua_flag2.sscp_exp: Indicates SSCP expedited flow if set to 1.
lua_flag2.sscp_norm: Indicates SSCP normal flow if set to 1.
lua_flag2.lu_exp: Indicates LU expedited flow if set to 1.
lua_flag2.lu_norm: Indicates LU normal flow if set to 1.

lua_resv56

This supplied parameter is a reserved field used by SLI_OPEN and RUI_INIT. For all other LUA verbs, this parameter is reserved and should be set to zero.

lua_encr_decr_option

This parameter is a field for cryptography options. On RUI_INIT, only the following are supported:

lua_encr_decr_option = 0
lua_encr_decr_option = 128

For all other LUA verbs, this parameter is reserved and should be set to zero.