Envoy ACP/XF Application Programming Manual

System Procedure Call Specifics for EnvoyACP/XF
EnvoyACP/XF Application Programming Manual–132179
4-20
WRITE[X] Procedure
write-count input
INT:value
specifies how many bytes are to be retrieved from the application buffer. You supply
the value to EnvoyACP/XF.
Note that this value must include the two bytes used for MCW. If the WRITE[X]
call is transmitting an unnumbered command or response, the buffer need contain
only the MCW and write-count should be 2.
count-written output
INT:ref:1 (Use with WRITE)
INT .EXT:ref:* (Use with WRITEX)
is for wait I/O only. Count-written returns a count specifying how many bytes
were actually transmitted. Note that this value, like the write-count, also
includes the two bytes used for the MCW.
tag input
INT(32):value (Use with WRITE and WRITEX)
is for nowait I/O only. Tag is a double-word integer value that you supply; tag
uniquely identifies the particular nowait WRITE[X] call.
Condition Codes
MCW Format
The HDLC protocol ignores the contents of the MC; therefore your application should
set the MCW to 0. An application using ADCCP-ABM also should set the MCW to 0
for ordinary WRITE[X] calls.
The SDLC and ADCCP-NRM protocols require that your application supply valid
address and control-field information in the MCW with each WRITE[X] call. Your
application should set the MCW as follows:
•
In a point-to-point environment, set bits 8 through 15 of the MCW to 0.
•
In a multipoint environment, place a station index, referring to one of the stations
listed in the DEFINELIST call, into bits 8 through 15 of the MCW.
= (CCE) indicates that the WRITE[X] procedure was executed successfully.
= (CCL) indicates that an error occurred (call FILE_GETINFO_).