OSI/AS Programming Manual

APS_TYPEDDATA_REQ_
APS Procedure Calls
056783 Tandem Computers Incorporated 3–107
block-size input
INT:value
is an optional parameter that determines how user data is to be sent. By default,
APS sends data to the TAPS process in 30,042-byte blocks. This parameter enables
you to specify smaller block sizes for individual requests, and thereby increase
throughput.
The valid values for this parameter are 1,000 to 30,042. If you supply a value
outside that range, OSI/AS returns the error condition ZAPS-ERR-PARAM-
RANGE.
Considerations
You should not invoke any other primitives while the typed data request primitive
is in progress. A typed data request primitive is considered to be in progress
whenever the more-data parameter is set to ZAPS-VAL-DATA-MORE.
The following examples show how you would typically set the more-data
parameter:
One call to send all data: ZAPS-VAL-DATA-NOVALUE or omit the parameter
First of three calls: ZAPS-VAL-DATA-MORE
Second of three calls: ZAPS-VAL-DATA-MORE
Third of three calls: ZAPS-VAL-DATA-NOVALUE or omit the parameter
You need not send any data to end the primitive; you can set the length in the data
element header to zero. In this case, however, OSI/AS still performs a file-system
I/O operation to the TSP process. It is best, therefore, to send data while ending
the primitive, by omitting the data-operation parameter or setting its value to
ZAPS-VAL-DATA-NOVALUE.
For presentation and ACSE connections, although an unlimited amount of user
data may be sent using multiple structures, the data is received by the remote
application as one presentation data value (PDV) list. You must begin each data
element header on a word boundary; pad it with a null byte if necessary.
For presentation and ACSE connections, you can send several data elements, each
having a different presentation context definition identifier (PCID) or the same
PCID.