ZCOM Tables and Data Structures
Queue Header
Table | Queue Header Structure (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
102 | Chapter 3 |