Return status.
0 - no error
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 may be used to retrieve a status message by calling zcomstatus(3X).
1. If zsend(3X) was used to send data using modes 1, 2, 5, or 7, then the 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.
rstat (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.
ZCOM C I/F Library Routines
ZREAD (3X)
ibuf (Return Param) Buffer for the received data.
lenMaximum length in bytes of the buffer ibuf. rlen (Return Param)
NOTES
Chapter 4 | 271 |
