ZCOM Tables and Data Structures
Queue Header
Queue Header
The queue header area contains the descriptor block for all the ZCOM subsystem queues. The first queue is used to link the free buffers in the buffer pool.
Figure
Queue Header 0 (Free Queue)
Queue Header 1
…
…
Queue Header n
Free Queue Header (zfqh_type), queue 0, basically is the same as the other buffer queues. However, its fields are viewed and used slightly differently from the other queues. Its size is the same as a buffer queue.
Table | Free Queue Header Structure (zfqh_type) |
| ||
|
|
|
| |
Field Name | Field Description | Field Type | Size | |
(Bytes) | ||||
|
|
| ||
|
|
|
| |
QNMSG | Number of messages on queue | uns.int | 4 | |
|
|
|
| |
QALLOC | Number of allocated messages | 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 | |
|
|
|
| |
|
|
|
| |
Chapter 3 | 101 |