ACC Programmer's Reference Guide

Chapter 4 271
ZCOM C I/F Library Routines
ZREAD (3X)
NOTES 1. If zsend(3X)wasusedtosenddatausingmodes1,2,5,or7,thenthe
input ZLU queue may contain response status messages. If the sent
message could not be delivered by the driver (e.g., data corruption in
the host system), an error response is returned to the sender’s
primary ZLU. When such an error response is picked up by zread,the
function returns with zero (indicating no problem in reading the
input ZLU), the returned message type is set (e.g.,
ZCOM_MSTYPE_RSLT) and the return status will carry a negative
ZCOM error code. If the message could not be delivered by the
interface (e.g., a problem with the terminal line), the returned
response will have a positive ZCOM status code indicating the
problem.
ibuf (Return Param) Buffer for the received data.
len Maximum length in bytes of the buffer ibuf.
rlen (Return Param) Actual data length. NULL may be specified if the
caller does not require the returned message length.
Note that rlen may exceed len. This indicates the
received data is truncated to just fill up ibuf.
rstat (Return Param) Return status.
0 - no error
-ve - ZCOM error code
+ve - terminal error status
It is meaningful only if the returned message is a
response or terminal message. For other message
types, it is always returned with zero. NULL may be
specified if the caller does not require this return
status.
The return status rstat and the request code
mhp->mrq.mrqcode maybeusedtoretrieveastatus
message by calling zcomstatus(3X).