HP 3000 Manuals HP 3000 Manuals
IPCSEND
Sends data on a connection.
Syntax
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| IPCSEND ( vcdesc, data, dlen[, flags][, opt], result)|
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Parameters
vcdesc (input)
32-bit integer, by value. The VC socket descriptor, a number identifying
the VC socket belonging to this process through which the data will be
sent.
data (input)
Record or byte array, by reference. Contains the data to be sent or a
list of data descriptors (maximum of two) indicating the locations from
which the data will be gathered. If data descriptors are used, flags
[31] must be set to indicate vectored sends. For programming in "C"
language, see Appendix E, C Programming Language Considerations.
dlen (input)
32-bit integer, by value. The byte length of the data parameter: that
is, the amount of actual data (maximum of 30,000) or the combined length
of the data descriptors. The data descriptor length is 8 for
compatibility mode and 12 for native mode. The combined length is 16 for
compatibility mode and 24 for native mode.
flags (input)
32 bits, by reference. A bit representation of various options. The
only flag defined is:
* flags [31]--vectored input. Indicates that the data to be sent are
to be gathered from the addresses specified in the data parameter.
(The parameter will not contain actual data.)
opt (input)
Record or byte array, by reference. A list of options, with associated
information. Refer to "Common Parameters" for more information on the
structure of this parameter. The following options are defined:
* data offset (code=8, length=2; 2-byte integer) (input).
Compatibility mode (CM) only. An offset in bytes from the data
parameter's address indicating the actual beginning of the data. HP
recommends that you do not use data offset if data descriptors are
used to point to another location from which data should be obtained.
* protocol flags (code=144, length=4; 4-byte buffer) (input). This
option contains 32 bits of protocol-specific flags. The following
flag is currently defined:
* end-to-end acknowledgement (bit 18, input). (X.25 only.) D bit
will be set in the last X.25 data packet corresponding to this
message. When this flag is set, IPCSEND waits to complete until
acknowledgement from the remote that the complete message has
been received. When the connection is between two HP 3000's
running NS X.25 , the acknowledgement is made when the remote IPC
user has received the data.
* qualifier bit (bit 19, input). (X.25 only.) This flag indicates
to X.25 to set the Q bit in the packets that contain this
message.
* urgent data (bit 27, input). (TCP only). If set, this bit will
cause the data sent to be marked urgent.
result (output)
32-bit integer, by reference. The error code returned; zero if no error.
NOTE When nowait I/O is used, the result parameter is not updated upon
completion of IOWAIT. Therefore, the value of result will indicate
only whether the call was successfully initiated. To determine
whether the call completed successfully, you can use the IPCCHECK
intrinsic after IOWAIT completes.
Description
The IPCSEND intrinsic is used to send data on a connection. The only
required parameters are vcdesc, data, and dlen (option variable).
A set of addresses in the data parameter allows vectored data to be
gathered from multiple locations.
The value specified for the data offset option (compatibility mode only)
is relative to the data array. If data descriptors are used, specifying
this option will cause a portion of the descriptor to be passed over (the
offset is NOT applied to the pointer in the descriptor). This may lead
to unexpected results.
If this intrinsic is called in nowait mode, the address of the data is
passed to the TCP protocol module. The contents of the data buffer will
have been read when IOWAIT completes. As many as 7 nowait sends may be
outstanding on a connection.
Condition codes returned by IPCSEND and IOWAIT are:
* CCE--Succeeded.
* CCL--Failed.
* CCG--Not returned.
This intrinsic can be called in split stack mode.
Protocol-Specific Considerations
The following table outlines parameters that are specific to the
particular protocol you are accessing.
Table 3-10. IPCSEND Protocol Specific Parameters
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| Parameters | TCP | X.25 |
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| opt | | |
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| 144 | Bit 27: urgent data | Bit 18: state of D bit in |
| | | X.25 packets |
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| | | Bit 19: state of Q bit in |
| | | X.25 packets |
| | | |
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X.25 Considerations
Setting the Q bit flag causes X.25 to set the Q bit (qualifier bit) in
X.25 data packets.
Setting the D bit flag causes X.25 to specify end-to-end acknowledgement
of data packets. IPCSEND does not complete until it receives
acknowledgement that the message has been received.
Common errors returned by IPCSHUTDOWN in result are:
SOCKERR 0 Request completed successfully.
SOCKERR 50 Invalid data length.
SOCKERR 65 Connection aborted by local protocol
module.
SOCKERR 67 Connection failure detected.
SOCKERR 107 Transport is going down.
SOCKERR 159 Invalid X.25 D-bit setting.
SOCKERR 160 Incompatible with protocol state.
A complete table of SOCKERRs is included in Appendix C.
TCP
The urgent data bit of the protocol flags option ( opt parameter) is used
to inform TCP that the data to be sent should be marked urgent. This
will not cause the data to be delivered out of band, and the receiver of
this data will not know of urgent data that is pending until a receive is
posted.
Cross-System Considerations For TCP
The following are cross-system programming considerations for this
intrinsic:
HP 3000 to HP 1000
Send size - The HP 3000 send size range is 1 to 30,000 bytes. The HP
1000 send size is 1 to 32,767 bytes. Although the ranges are different,
cross-system communication is not affected. If you specify a send or
receive size, be sure it is within the correct range for the respective
system.
Note that the urgent data bit is not supported on the HP 1000; however,
if this bit is set by the HP 3000 program, it will be ignored by the
receiving process on the HP 1000.
HP 3000 to HP 9000
Send size - The HP 3000 send size range is 1 to 30,000 bytes. The HP
9000 send size is 1 to 32,767 bytes. Although the ranges are different,
cross-system communication is not affected. If you specify a send or
receive size, be sure it is within the correct range for the respective
system.
Note that the urgent data bit is not supported on the HP 9000; however,
if this bit is set by the HP 3000 program, it will be ignored by the
receiving process on the HP 9000. For differences in send and receive
sizes see the discussion for IPCRECVCN.
HP 3000 to PC NetIPC
Send size - The PC send and receive size range is 1 to 65,535 bytes.
Although the ranges are different, cross-system communication is not
affected. If you specify a send or receive size, be sure it is within
the correct range for the respective system.
On the PC, you can specify the maximum receive size of the data buffer
through the got array in the IPCCONNECTcall. This determines what the
maximum value for dlen can be for any IPCRECV call. PC NetIPC has no
option array defined for IPCCONNECT. This does not affect cross-system
communication. The maximum receive size of the data in the buffer on the
HP 3000 will determine the receive size buffer on the PC.