N.B.: The implementation of message data transfer may not work correctly if the SEND and RECEIVE areas (or the ANSWER and REPLY areas) overlap. IBM documentation is vague on this point.

VMGIUCVP(accept{=0},
(2,pathid),(2,msglim),(1,flags),(16,userdata);S==> rc,(2,msglim),(1,flags)) Accept an IUCV Connection

pathid - Will be used to identify this path in CP Group Communication key messages.

msglim - Maximum number of outstanding messages on the path (1-255). 0 means unspecified.

Flags are:

X'20' - Allow sending priority messages

X'40' - (quiesce) Forbids the source VM from sending messages until you do a resume operation.

X'80' - Message data can be handled in the parameter list.

Other bits must be zero.

Userdata - passed as part of the connect operation.

S - The segment that will contain the target's IUCV message buffers (i.e. the virtual machine's real memory segment).

Returned string:

msglim(i2) - the message limit for the path

flags(x1) - contains:

X'20' - indicates the target may send priority messages

Return code is:
0 - Connection accept complete.

1 - Connection not pending, or this is the source path key (must be accepted by the target)

18 - msglim > 255

kt+1 - Path severed already

userdata - Data to be sent to other end of path.

Return code:

0 - Done

kt+1 - connection has been severed already

Msgid - The message ID of the message to be rejected.

targetclass - The target class of the message

Input flags are:

X'01' - Target class has been specified.

X'04' - Message ID has been specified

Return Code is:
-2 - No message found

0 - Message Rejected

Messageid - The message ID of the message rejected.

targetclass - The target class of the message rejected

1 - The connection is not complete (not yet ACCEPTed)

8 - Message found but message class invalid.

userdata - Data to be sent to other end of path.

Return code:

0 - Done

1 - The connection is not complete (not yet ACCEPTed)

kt+1 - connection has been severed

userdata - Data to be sent to other end of path.

Return code:

0 - Done

1 - The connection is not complete (not yet ACCEPTed)

kt+1 - connection has been severed

msgaddr - The address of the message buffer or the message buffer list in the segment passed as part of the connect or accept key call.

msglength - Length of message to be sent or the sum of the message buffer list lengths.

replyaddr - The address of the reply buffer or of the reply buffer list in the segment passed as part of the connect or accept key call.

maxreplylen - Maximum length of the expected reply or the sum of the lengths in the reply buffer list.

targetclass - value passed to target VM. Can be used for message selection

sourceclass - value returned with the "Message Complete" messge. Can be used for message selection when purging a message.

tag - Returned with the "Message Complete" message. Not passed to the target VM.

Flags are:

X'08' - Reply buffer list in use. Replyaddr is doubleword aligned address of the list and maxreplylen is the sum of lengths in the list.

X'10' - One way message, No reply expected

X'20' - Send this as a priority message

X'40' - Message buffer list in use. Msgaddr is doubleword aligned address of the list and msglength is the sum of lengths in the list. The X'80' flag must be off.

X'80' - Message data is included in the parameter string. The data is the 8-byte field consisting of the combined msgaddr and msglength fields. If this bit is zero, msgaddr is an address in the segment specified on the connect or accept operation.

Other bits must be zero.

Return Code is:
0 - Message send pending
Msgid - The message ID assigned to this message.

1 - The connection is not complete (not yet ACCEPTed)

2 - Path Quiesced

3 - Message limit exceeded

4 - Priority messages not accepted

10 - Negative message length

21 - Message in jump not permitted on path

25 - Flags & X'40' and flags & X'80' not valid

Note: the CP function IUCV RECEIVE allows selection of a message based on the path id and/or target class, rather than just based on the msgid. The CP simulator must use this information to determine the correct msgid before calling VMGIUCVP.

Passed string:

Msgid - The message ID of the message to be received.

inaddr - The address of the receive buffer or of the receive buffer list in the segment provided on the connect or accept key call.

length - The length of the receive buffer or the sum of the lengths in the buffer list

inflags are:

X'40' - Receive buffer list in use. Inaddr is address of the list and length is the sum of lengths in the list.

Returned string:
outflags are:
X'10' - indicates that this is a one-way message and no reply is expected.

X'20' - indicates that this is a priority message

X'80' - If this bit is on, the 8-byte message is contained in (n,data) and n is 8. If this bit is off, (n,data) contains a count as described under return codes 0 and 5, and n is 4.

replylen - contains the length of the expected reply.

outaddr - contains the updated address in the buffer or buffer list.

Return Code is:
-5 - Addressing exception on the receiver's buffer or buffer list. No string is returned.

-4 - Protection exception on the receiver's buffer or buffer list. No string is returned.

-2 - Message ID not found. No string is returned.

0 - Message Received

If (outflags & X'80') Then (8,data) is the message. Else (4,data) has the count of bytes remaining in the receive buffer

1 - The connection is not complete (not yet ACCEPTed). No string is returned.

5 - Receive buffer too short for the message. Message remains outstanding. The rest of the message may be received with subsequent receive operations.

(4,data) - Number of bytes remaining in the message.

6 - Fetch protection on send buffer. No string is returned.

7 - Addressing exception on send buffer. No string is returned.

9 - Message has been purged. No string is returned.

10 - Length < 0. No string is returned.

22 - Send buffer list invalid. No string is returned.

23 - Negative length in buffer list. No string is returned.

24 - Incorrect total length of buffer list lengths. No string is returned.

Msgid - The message ID of the message to be replied to.

addr - The address of the reply buffer or of the reply buffer list in the segment provided on the connect or accept key call.

length - The length of the reply buffer or the sum of the lengths in the buffer list

Flags are:

X'08' - Reply buffer list in use. Addr is doubleword aligned address of the list and length is the sum of lengths in the list.

X'20' - Priority reply

X'80' - Reply data included in string. Addr and length are two halves of an 8-byte field containing the reply data.

Return Code is:
-5 - Addressing exception on the replyer's buffer or buffer list

-4 - Protection exception on the replyer's buffer or buffer list

-2 - Message ID not found

0 - Reply sent

count - Remaining length in the answer buffer

1 - The connection is not complete (not yet ACCEPTed)

5 - Answer buffer too short for the message.

count - Number of bytes remaining in the reply.

6 - Storage protection exception on answer buffer
count - Number of bytes remaining in the reply.

7 - Addressing exception on answer buffer
count - Number of bytes remaining in the reply.

9 - Message has been purged

10 - Length < 0

21 - flags & X'80' not permitted on this path

22 - Answer buffer list invalid

23 - Negative length in buffer list

24 - Incorrect total length of buffer list lengths

25 - Flags & X'08' and flags & x'80' not permitted

Msgid - The message ID of the message to be purged.

sourceclass - The source class of the message

Input flags are:

X'01' - Source class has been specified.

X'04' - Message ID has been specified

Return Code is:
-2 - No message found

0 - Message Purged

Messageid - The message ID of the message purged.

sourceclass - The source class of the message purged.

tag - The tag of the message purged.

Output flags are:

X'10' - The purged message was a one-way message.

X'20' - The purged message was a priority message.

1 - The connection is not complete (not yet ACCEPTed)

8 - Message found but message class invalid.