HP UX 11i v1 I/O Cards manual Qlimit, Qfdata, Qfunc

ZCOM Tables and Data Structures

Queue Header

Table 3-28	Queue Header (zqhd_type)
Field Name	Field Description	Field Type	Size
			(Bytes)
QNMSG	Number of messages on queue	uns.int	4
QLIMIT	Max messages/bytes allowed on queue	uns.int	4
QHEAD	Pointer to first message on queue	pointer	8
QTAIL	Pointer to last message on queue	pointer	8
QMMAX	Historical max number of messages	uns.int	4
QTMSG	Total messages through queue	uns.int	4
QBYTES	Number of bytes on queue	uns.int	4
QWAITER	Number of waiters on this queue	uns.short	2
QFLAG	Queue flags	uns.short	2
QFDATA	Queue function data	uns.int	4
SPARE1	Reserved, not used	int	4
QFUNC	Queue function	pointer	8

QNMSG - Number on queue

Counter of the number of messages on the queue. When this is zero the queue is empty.

QALLOC - Number of allocated messages

This field is used in the free queue header to keep track of the number of buffer segments allocated for ZCOM subsystem use. A value of zero means that no buffers have been allocated for use by the ZCOM subsystem. A large value indicates heavy usage of the buffer pool.

QLIMIT - Queue limit

The maximum number of messages or bytes that may be linked to this queue. If the ZCOM_QFLAG_BLT bit in qflag is not set, this field is a limit on the number of messages. Otherwise, this value is a limit on the number of bytes that can be linked to this queue. The default queue limit is initialized from the Queue-Limitparameter in the TTGEN configuration file when the queue is initialized. The queue limit may be modified dynamically by calling the zsetql routine.

98 Chapter 3