There is no way to require the user to use this function. It is
not a required function so that the application can be tailored to
run on any system.
The buffer sizes returned represent the record sizes that are
actually transmitted across the medium. For a DDM connection, the
8-byte header supplied in the Read and Write Structured Fields data buffer is stripped
off and 1 byte containing the structured field AID value is prefixed.
The application should compare the size of the actual data in the
data buffer (which does not include the 8-byte header) with the buffer
sizes returned by the Query Communications Buffer
Size minus 1 byte. For destination/origin connections, the 8-byte
header supplied in the Read and Write
Structured Fields data buffer is stripped off and 9 bytes are
then prefixed to the data. The application should compare the size
of the actual data in the data buffer (which does not include the
8-byte header) with the buffer size returned by the Query
Communications Buffer Size minus 9 bytes.
The maximum buffer sizes returned represent the maximum number
of bytes supported by the workstation hardware and by the emulator.
The maximum buffer size can be used only if the host is also configured
to accept at least these maximum sizes.
The optimum buffer sizes returned represent the optimum number
of bytes supported by the both the workstation hardware and the emulator.
Some network configurations might set transmission limits smaller
than these values. In these cases, the data transfer buffer size override
value in the emulator configuration profile will be used for structured
field support. The Query Communications Buffer Size will
reflect any buffer size override values entered in the emulator configuration
profile.