NetIPC 3000/XL Programmer's Reference Manual (5958-8600)

Chapter 3 113
NetIPC Intrinsics
IPCRECVCN
Common errors returned by IPCRECVCN in result are:
SOCKERR 0 Request completed successfully.
SOCKERR 59 Socket timeout.
SOCKERR 107 Transport is going down.
A complete table of SOCKERRs is included in Chapter C ,
“Error Messages.”
TCP
The calling process may also specify whether checksumming is to be
employed by the protocol modules (i.e., TCP) that support it. For TCP,
checksumming is usually disabled unless it is included by the remote
protocol module or if the TCP checksumming flag (
flags [21]) is set.
When checksumming is enabled, performance is usually degraded
because of increased overhead.
Cross-System Considerations For TCP
The following are cross-system programming considerations for this
intrinsic:
HP 3000 to HP 1000: Checksumming — TCP checksumming will be
enabled for both sides of the connection if it is enabled by either side for
HP 3000 to HP 1000 connections. On both the HP 3000 and HP 1000
checksumming can be enabled by setting bit 21 in the
flags parameter.
Send and receive size — The HP 3000 send and receive size range is
1 to 30,000 bytes. The HP 1000 send and receive size range is 1 to 8,000
bytes. Although the ranges are different, you must specify a send size
within the correct range for the respective receiving system; otherwise,
an error will occur. For example, if the HP 3000 node sends 16,000
bytes, the HP 1000 node can call IPCRECV twice receiving 8,000 bytes
the first time and the second 8,000 bytes the second time.
Note that the default send and receive sizes are different on different
HP systems. On the HP 3000, the default send and receive size is less
than or equal to 1,024 bytes. On the HP 1000 the default send and
receive size is 100 bytes.
HP 3000 to HP 9000: Checksumming — When the ipcrecvcn() call
is executed on the HP 9000 node, checksumming is always enabled.
Send and receive sizes — The HP 3000 send and receive size range is
1 to 30,000 bytes. The HP 9000 send and receive size range 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 default send and receive sizes are different on different
HP systems. On the HP 3000, the default send and receive size is less
than or equal to 1,024 bytes. On the HP 9000, the default send and