AM3270/TR3271 Reference Manual

Details of the ITI Protocol
AM3270 Subdevice Protocols
086705 Tandem Computers Incorporated 4–5
filenumber
the file number provided by OPEN—this is an INT:value.
function
function code is 3; will set or fetch parameters for BREAK handling—this is an
INT:value.
param array
a list or string as required by function—this is passed by reference (INT:ref:1).
param count
the number of bytes contained in param array—this is an INT:value.
last param array
the returned previous parameter settings associated with function—this is passed
by reference (INT:ref:1).
last param count
the returned length of last param array in bytes—this is passed by reference
(INT:ref:1). The maximum is 256 bytes.
Using SETPARAM with a function code of 3 simultaneously sets both the ownership
of BREAK and the value of a 32-bit BREAK tag. When BREAK is detected, the owner
of BREAK also receives a BREAK interprocess message containing the BREAK tag.
The purpose of the tag is to support applications which own BREAK on several
subdevices at the same time. Appropriate use of BREAK tags allows such applications
to distinguish among BREAK messages received from any of the subdevices.
To use SETPARAM in this manner, the call syntax is:
CALL SETPARAM (filenumber, 3, buf, count, oldbuf, oldcount)
If buf and count are specified, the new values for BREAK handling are set from the
contents of buf.
If count is specified and its value is not equal to 8, the operation will fail with a file-
system error 21 (illegal count specified).
If oldbuf and oldcount are specified, the old values for the BREAK handling
parameters are returned to oldbuf, while oldcount is set to 8.
Buf and oldbuf are integer arrays containing:
buf[0] the equivalent to parameter 1 of SETMODE 11.
buf[1] the equivalent to parameter 2 of SETMODE 11.
buf[2] the most significant word of the BREAK tag.
buf[3] the least significant word of the BREAK tag.
buf[0] 0 disable BREAK (default setting).