Reference Guide

ZCOM C I/F Library Routines
ZSEND (3X)
Chapter 4310
NOTES If mhp is specified (i.e., a non-NULL pointer), some header fields must be
set up by the caller because they are extracted and sent with the data
buffer. These fields are:
The other header fields are set up by the ZCOM subsystem exclusively.
The source ZCOM address field provides a way to redirect the response
to a different ZLU rather than the primary ZLU. The Primary ZLU is
used if it is zero. The two header tag words provide a means of
identifying the response in the case where a “no wait” mode is used. The
protocol tag parameter controls special options supported by the protocol
module (protocol specific). Refer to the relevant Protocol Manual for its
use.
It is important to zero out undesirable fields to avoid unexpected results.
For example, if the caller only wants to specify the two header tag words,
then the source ZLU and protocol tag must be zeroed out. If NULL is
specified for mhp, zsend defaults the source ZLU to the primary ZLU and
the rest to zeros.
If bit ZCOM_ZSEND_MHD (0x8000) of mode is set, zsend allows more
header fields to be specified by the caller, hence having more control in
the message sent. This implies mhp must be specified, i.e., non-NULL.
The header fields that must be set up by the caller are:
mhp->mid.mzsrce - source ZCOM address (ZLU)
mhp->mid.mtagw1 - header tag word 1
mhp->mid.mtagw2 - header tag word 2
mhp->mrq.mrqtag - protocol tag parameter (for terminal ZLU only)
mhp->mid.mstype - message type
mhp->mid.msresp - message response code
mhp->mid.mzdest - destination ZCOM address
mhp->mid.mzsrce - source ZCOM address
mhp->mid.mtagw1 - header tag word 1
mhp->mid.mtagw2 - header tag word 2
mhp->mid.mzaux1 - auxiliary ZCOM address