Envoy ACP/XF Application Programming Manual

System Procedure Call Specifics for EnvoyACP/XF
EnvoyACP/XF Application Programming Manual–132179
4-11
READ[X] Procedure
read-count input
INT:value (Use with both READ and READX)
specifies how many incoming bytes can be placed in the application buffer. You
must supply this value to EnvoyACP/XF. Note that this value must include the two
bytes used for the MCW.
count-read output
INT:ref:1 (Use with READ)
INT .EXT:ref:1 (Use with READX)
is the name of a one-word integer variable into which EnvoyACP/XF sets a value
specifying how many bytes were actually placed in the application buffer. Note that
this value, like the count-read, also includes the two bytes used for the MCW.
tag input
INT(32):value (Use with both READ and READX)
is for nowait I/O only. tag is a double-word integer value that uniquely identifies
the nowait READ[X] call. You supply this value to EnvoyACP/XF.
For READ[X] requests, the format of the MCW is:
Bit 0 = 0: When the current READ[X] request was completed at the link
level, additional received frames were in the local input queue.
= 1: When the current READ[X] request was completed at the link
level, no more received frames were in the local input queue.
Bit 1 = 0: The received frame is an I-frame.
= 1: The received frame is a command or response U-frame.
Bit 2 = 0: The information field is present in the received command or
response U-frame.
= 1: No information field is present in the received command or
response.