RUI_WRITE

The RUI_WRITE verb sends an SNA request or response unit from the LUA application to the host over either the LU session or the SSCP session, and sends responses, SNA commands, and data from a Windows LUA application to the host LU.

The following structure describes the LUA_COMMON member of the VCB used by RUI_WRITE.

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;
};

Members

lua_verb
Supplied parameter. Contains the verb code, LUA_VERB_RUI for RUI verbs.
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, LUA_OPCODE_RUI_WRITE.
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.

RUI_WRITE only requires 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
Not used by RUI in Microsoft® SNA Server and should be set to zero.
lua_cobol_offset
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
Not used by RUI_WRITE and should be set to zero.
lua_data_length
Returned parameter. Specifies the length of data returned in lua_peek_data for the RUI_BID verb.
lua_data_ptr
Points to the buffer containing the data to be sent to the host by RUI_WRITE.

Both SNA commands and data are placed in this buffer, and they can be in an EBCDIC format.

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. Its 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. For the RH for RUI_WRITE, all fields except the queued-response indicator (lua_rh.qri) and pacing indicator (lua_rh.pi) are used. 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. 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.

Set one of the following flags to 1 to indicate on which message flow the data is to be sent:

lua_flag1.sscp_exp

lua_flag1.sscp_norm

lua_flag1.lu_exp

lua_flag1.lu_norm

lua_message_type
Not used by RUI_WRITE and should be set to zero.
lua_flag2
Returned parameter. Contains flags for messages returned by LUA. 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
Reserved and should be set to zero.
lua_encr_decr_option
Reserved and should be set to zero.

Return Codes

LUA_OK
Primary return code; the verb executed successfully.
LUA_CANCELED
Primary return code; the verb did not complete successfully because it was canceled by another verb.
LUA_TERMINATED
Secondary return code; the verb was canceled because RUI_TERM was issued for this session.
LUA_PARAMETER_CHECK
Primary return code; the verb did not execute because of a parameter error.
LUA_BAD_DATA_PTR
Secondary return code; the lua_data_ptr parameter contained an invalid value.
LUA_BAD_SESSION_ID
Secondary return code; an invalid value for lua_sid was specified in the VCB.
LUA_DUPLICATE_WRITE_FLOW
Secondary return code; RUI_WRITE was already outstanding for the session flow specified on this verb (the session flow is specified by setting one of the lua_flag1 flow flags to 1). Only one RUI_WRITE at a time can be outstanding on each session flow.
LUA_INVALID_FLOW
Secondary return code; the lua_flag1.sscp_exp flow flag was set, indicating that the message should be sent on the SSCP expedited flow. LUA does not allow applications to send data on this flow.
LUA_INVALID_POST_HANDLE
Secondary return code; for a Windows NT or Windows 95 system using events as the asynchronous posting method, the Windows LUA VCB does not contain a valid event handle.

For the Windows version 3.x system, the Windows LUA VCB does not contain the valid procedure address returned by the MakeProcInstance command.

For OS/2, the Windows LUA VCB does not contain a valid semaphore or queue handle, which is needed when the verb completes asynchronously.

LUA_MULTIPLE_WRITE_FLOWS
Secondary return code; more than one of the lua_flag1 flow flags was set to 1. One and only one of these flags must be set to 1, to indicate which session flow the data is to be sent on.
LUA_REQUIRED_FIELD_MISSING
Secondary return code; indicates one of the following cases:
·    None of the lua_flag1 flow flags was set. One and only one of these flags must be set to 1.
·    RUI_WRITE was used to send a response, and the response required more data than was supplied.

LUA_RESERVED_FIELD_NOT_ZERO
Secondary return code; a reserved field in the verb record or a parameter not used by this verb was set to a nonzero value.
LUA_VERB_LENGTH_INVALID
Secondary return code; an LUA verb was issued with the value of lua_verb_length unexpected by LUA.
LUA_STATE_CHECK
Primary return code; the verb did not execute because it was issued in an invalid state.
LUA_MODE_INCONSISTENCY
Secondary return code; the SNA message sent on RUI_WRITE was not valid at this time. This is caused by trying to send data on the LU session before the session is bound. Check the sequence of SNA messages sent.
LUA_NO_RUI_SESSION
Secondary return code; RUI_INIT has not yet completed successfully for the LU name specified on this verb.
LUA_UNSUCCESSFUL
Primary return code; the verb record supplied was valid, but the verb did not complete successfully.
LUA_FUNCTION_NOT_SUPPORTED
Secondary return code; indicates one of the following cases:
·    The lua_rh.fi bit (format indicator) was set to 1, but the first byte of the supplied RU was not a recognized request code.
·    The lua_rh.ruc parameter (RU category) specified the network control (NC) category; LUA does not allow applications to send requests in this category.

LUA_INVALID_PROCESS
Secondary return code; the OS/2 process that issued this verb was not the same process that issued RUI_INIT for this session. Only the process that started a session can issue verbs on that session.
LUA_INVALID_SESSION_PARAMETERS
Secondary return code; the application used RUI_WRITE to send a positive response to a BIND message received from the host. However, SNA Server cannot accept the BIND parameters as specified, and has sent a negative response to the host. See SNA Considerations for more information on the BIND profiles accepted by SNA Server.
LUA_RSP_CORRELATION_ERROR
Secondary return code; when using RUI_WRITE to send a response, lua_th.snf (which indicates the sequence number of the received message being responded to) did not contain a valid value.
LUA_RU_LENGTH_ERROR
Secondary return code; the lua_data_length parameter contained an invalid value. When sending data on the LU normal flow, the maximum length is as specified in the BIND received from the host; for all other flows the maximum length is 256 bytes.

Note Any other secondary return code is an SNA sense code indicating that the supplied SNA data was invalid or could not be sent. See SNA Considerations for information on interpreting the SNA sense codes that can be returned.

LUA_COMM_SUBSYSTEM_ABENDED
Primary return code; indicates one of the following conditions:
LUA_SESSION_FAILURE
Primary return code; a required SNA Server component has terminated.
LUA_LU_COMPONENT_DISCONNECTED
Secondary return code; indicates that the LUA session has failed because of a problem with the link service or with the host LU.
LUA_RUI_LOGIC_ERROR
Secondary return code; an internal error was detected within LUA. This error should not occur during normal operation.
LUA_INVALID_VERB
Primary return code; either the verb code or the operation code, or both, is invalid. The verb did not execute.
LUA_STACK_TOO_SMALL
Primary return code; the stack size of the application is too small to execute the verb. Increase the stack size of your application.
LUA_COMM_SUBSYSTEM_NOT_LOADED
Primary return code; a required component could not be loaded or has terminated while processing the verb. Thus, communication could not take place. Contact the system administrator for corrective action.
LUA_UNEXPECTED_DOS_ERROR
Primary return code; after issuing an operating system call, an unexpected operating system return code was received and is specified in the secondary return code.

Remarks

RUI_INIT must be issued successfully before this verb is issued.

When sending an SNA request, all applicable values in the lua_rh must be set. Chaining and bracketing are the responsibility of the application.

When sending a response, the type of response determines the RUI_WRITE information required. For all responses, you must:

For multichain message responses, the sequence number of the last received chain element must be used. For a response to a multichain message ending with a CANCEL command, the CANCEL command sequence number is used.

For positive responses that only require the request code, set lua_rh.ri to zero (indicating that the response is positive) and lua_data_length to zero (indicating that no data is provided). The request code is filled in by the RUI, using the sequence number provided.

For negative responses, set lua_rh.ri to 1, lua_data_ptr to the SNA sense code address, and lua_data_length to the SNA sense code length (four bytes). The sequence number is used by the RUI to fill in the request code.

For positive responses to the BIND and STSN commands that require data in the responses, set lua_data_ptr to point to the response and set lua_data_length to the length of the data provided in lua_data_ptr.

While an existing RUI_WRITE is pending, you can issue a second RUI_WRITE only if it specifies a different session flow from the pending RUI_WRITE. That is, you cannot have more than one RUI_WRITE outstanding for the same session flow.

RUI_WRITE can be issued on the SSCP normal flow at any time after a successful RUI_INIT. RUI_WRITE verbs on the LU expedited or LU normal flows are permitted only after a BIND has been received, and must abide by the protocols specified on the BIND.

Note that successful completion of RUI_WRITE indicates that the message was queued successfully to the data link; it does not necessarily indicate that the message was sent successfully, or that the host accepted it.

Pacing can be used on the secondary-to-primary half-session (specified on the BIND) to prevent the LUA application from sending more data than the local or remote LU can handle. If this is the case, an RUI_WRITE on the LU normal flow may be delayed by LUA and may take some time to complete.

See Also

RUI_INIT, RUI_READ, RUI_TERM, SLI_OPEN, SLI_PURGE, SLI_RECEIVE, SLI_SEND