What Data Structures Does PHONBOOK Use?

Figure 1 illustrates the data structures that the PHONBOOK routine uses to do its work. When each member joins the group, the member specifies as member data (MEMDATA parameter on IXCJOIN) the address of the MDATASTR data structure. MDATASTR contains the following information:

Field name	Contents
TBLADDR	Address of the table created and maintained by the group user routine (the TABLE data structure).
NEXTITEM	Address of next available slot in the table.
MEMWQHDR	Address of the member's work queue.
DBWQHDR	Address of the DBMGR's work queue. (This field used only by the PRIMARY member.)
MAINECB	Address of the ECB that the main routine waits for.
TASKECB1	Address of the ECB that the CLEANUP task waits for, and the message user routine posts.
TASKECB2	Address of the ECB that the CLEANUP task waits for, and the group user routine posts.
XPRIMBU	Indicates a switch from PRIMARY to BACKUP. The group user routine turns this switch on the first time it is called for a status update missing.

The TABLE data structure contains the following information:

Field name	Contents
MEMNAME	The member's name.
MEMTOKEN	The member's token.
MEMSTATE	The member's state.
MEMUSTAT	The member's user state value.

The member's work queue and the DBMGR's work queue both consist of work elements (WRKELEMT). Each WRKELEMT contains a pointer to the next element on the queue, the requesting member, and the work to be done. If the pointer to the next element is zero, the queue is empty.

Figure 1. Data Structures Used by PHONBOOK Routine