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Creates a destination descriptor.
Syntax
IPCDEST ( socketkind [,location] [,locationlen], protocol,
protoaddr, protolen [,flags] [,opt], destdesc [,result] )
Parameters
- socketkind (input)
- 32-bit integer, by value. Defines the type of socket. The only
type user processes can create is: 3 = call socket.
- location (input)
- Character array, by reference. The name of the node (either
node or node.domain.organization) on
which the destination socket is to be created. If this parameter is
omitted, the local node is assumed.
- locationlen (input)
- 32-bit integer, by value. The length in bytes of the destination
node name. Zero indicates that no location was given (that is, the node
is local). Maximum (for a fully qualified name) is 50.
- protocol (input)
- 32-bit integer, by value. Defines the Transport Layer protocol to
be used. The protocols currently available to user processes are:
- 2 = X.25 protocol
- 4 = TCP
- protoaddr (input)
- Byte array, by reference. Protocol relative address (remote
address) with which the socket will be associated. The format of this
address, defined by the protocol, is a 2-byte array (16 bits).
Nonprivileged programs must use addresses in the range 30767 to 32767
decimal (%74057 to %77777). For X.25 access to level 3, this address is
included in the CUD field of an X.25 call packet. (See the discussion of
IPCCONNECT for the parameters providing access to the CUD).
- protolen (input)
32-bit integer, by value. The length in bytes of the protocol
address. - flags
- 32 bits, by reference. A bit representation of various options.
No flags are currently defined.
- opt (input)
- Record or byte array, by reference. A list of options, with
associated information.
- destination network address (code = 16, length=n, n byte buffer)
(input). (X.25 only.) This option allows a user to bypass the use
of the network directory and associated IP address by specifying
the destination node network address.
The first two bytes of the option data field contain the "protocol"
value of the module. For X.25, the protocol value is 2. The rest
of the option data field is relative to that protocol. For X.25,
two subformats are defined: one for the PVC numbers and one for
SVC addresses. The third and fourth bytes of the data field
contain a format identifier, where 1 indicates a PVC number and 0
indicates a SVC address. The PVC number is a 4 byte field. For a
PVC, the total length of the option field is 8 bytes.
The SVC field is composed of up to 16 nibbles where the first
nibble is the nibble length of the remaining address. An odd
number of nibbles can be passed since the length indicates the
significance of the remaining field. This implies that the option
data length for an SVC is between 5 and 12 bytes inclusive.
- destdesc (output)
- 32-bit integer, by reference. Destination descriptor. Describes
the location of the named call socket. May be used in subsequent NetIPC
calls to IPCCONNECT.
- result (output)
- 32-bit integer, by reference. The error code returned; zero if no
error.
Description
The IPCDEST intrinsic creates a destination descriptor that contains
routing information for sending data to another process.
This intrinsic is option variable. The required parameters are:
socketkind, protocol,
protoaddr, protolen, and
destdesc.
Condition codes returned by this intrinsic are:
- CCE — Succeeded.
- CCL — Failed.
- CCG — Not returned by this intrinsic.
This intrinsic cannot be called in split stack mode.
Protocol-Specific Considerations
The following Table 3-6 "IPCDEST Protocol
Specific Parameters" outlines parameters that are specific to the
particular protocol you are accessing.
Table 3-6 IPCDEST Protocol Specific Parameters
| Parameters |
TCP |
X.25 |
| opt | | |
| 16 | n/a | destination network address |
X.25 Considerations
IPCDEST is used to create a destination descriptor for X.25 direct
access. The protoaddr parameter is only used with switched
virtual circuits (SVCs).
Using the destination network address (opt 16) to directly
specify an X.25 address of an SVC or a PVC number allows the user to bypass
the use of the network directory and the associated IP address.
Cross-System Considerations For TCP
The following are HP 3000 to HP 1000, HP 3000 to HP 9000, and HP 3000 to PC
programming considerations for this intrinsic.
TCP protocol address — Although the ranges of protocol addresses
for each computer system are different, the recommended range of TCP addresses
for user applications is from 30767 to 32767 decimal (%74057 to %77777).
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