OSI/AS Programming Manual

APS_DATA_REQ_
APS Procedure Calls
056783 Tandem Computers Incorporated 3–69
primitive. To give tokens to the remote application, set the field values for the
tokens you are giving to ZAPS-VAL-TOKEN-GIVE, and set the field values for all
other tokens to ZAPS-VAL-TOKEN-NOVALUE.
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.
Considerations
You should not invoke any other primitives while the data request primitive is in
progress. A data request primitive is considered to be in progress whenever
more-data 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; instead, 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 more efficient, therefore, to send
data while ending the primitive, by omitting data-operation 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 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.