ACC Programmer's Reference Guide

272 Chapter4
ZCOM C I/F Library Routines
ZREAD (3X)
2. If the received message (or response) is from a terminal, the request
code is returned in mhp->mrq.mrqcode. The request code and the
returned status m ay be used to retrieve an appropriate s tatus/error
message by zcomstatus(3X). Refer to Appendix B ZCOM Status Codes
of the Multiprotocol ACC Programmers’ Reference Guide for more
information. The mhp->mrq.mrqcode field contains 0 if the message
is from a program or is a System Event Message (SEM).
3. A System Event Message (SEM) is generated by the ZCOM
subsystem in response to special events that occur within the ZCOM
subsystem. A program may choose to receive event messages by
supplying its p rimary ZLU in a zevent_rcvr call. All ZCOM Event
messages are divided into a header and event specific data section.
The header is defined for all types of Event messages while the data
portion depends on the ZCOM Event Message type. Refer to the
subsection ‘System Event Messages’ in the Multiprotocol ACC
Programmers’ Reference Guide for more information. The SEM’s
structure is defined in /opt/acc/include/zcom/zcomsys.h.
4. The tag parameters (mhp->mid.mtagw1 and mtagw2)arethetag
parameters from t h e originating zsend(3X) call.
5. The type of message received is returned in mhp->mid.mstype.Its
values are as follows (defined in /opt/acc/include/zcom/zcomsys.h):
#define ZCOM_MSTYPE_REMOTE 0x08 /* Mask for remote message bit */
#define ZCOM_MSTYPE____0 0 /* Undefined type */
#define ZCOM_MSTYPE_MSLT 1 /* From local terminal */
#define ZCOM_MSTYPE_LPLP 2 /* Local program to program */
#define ZCOM_MSTYPE_TOLZ 3 /* Timer message for local ZLU */
#define ZCOM_MSTYPE_LPLT 4 /* Local program to terminal */
#define ZCOM_MSTYPE_LSEM 5 /* Local system event message */
#define ZCOM_MSTYPE_RSLT 6 /* Response from local terminal */
#define ZCOM_MSTYPE_RSLP 7 /* Response from local program */
#define ZCOM_MSTYPE____8 8 /* Undefined type */
#define ZCOM_MSTYPE_MSRT 9 /* Remote terminal message */
#define ZCOM_MSTYPE_RPLP 10 /* Remote program to program */
#define ZCOM_MSTYPE_TORZ 11 /* Timer message for remote ZLU */
#define ZCOM_MSTYPE_RPLT 12 /* Remote program to terminal */
#define ZCOM_MSTYPE_RSEM 13 /* Remote system event message */
#define ZCOM_MSTYPE_RSRT 14 /* Response from remote terminal */
#define ZCOM_MSTYPE_RSRP 15 /* Response from remote program */