Coma FW-C2800 User's Guide download pdf (Page 201)

Queues

Memory and Low-level Functions 5-15

5.3.2 Other QUE Functions

Unlike QUE_get and QUE_put, there are a number of QUE functions that do

not disable interrupts when updating the queue. These functions must be

used in conjunction with some mutual exclusion mechanism if the queues

being modified are shared by multiple threads.

QUE_dequeue and QUE_enqueue are equivalent to QUE_get and QUE_put

except that they do not disable interrupts when updating the queue.

QUE_head is used to return a pointer to the first element in the queue without

removing the element. QUE_next and QUE_prev are used to scan the

elements in the queue—QUE_next returns a pointer to the next element in

the queue and QUE_prev returns a pointer to the previous element in the

queue.

QUE_insert and QUE_remove are used to insert or remove an element from

an arbitrary point within the queue.

Example 5-17. Using QUE Functions with Mutual Exclusion Elements

Note:

Since QUE queues are implemented as doubly linked lists with a header

node, QUE_head, QUE_next, or QUE_prev may return a pointer to the

header node itself (for example, calling QUE_head on an empty queue). Be

careful not to call QUE_remove and remove this header node.

Ptr QUE_dequeue(queue)

QUE_Handle queue;

Void QUE_enqueue(queue, elem)

QUE_Handle queue;

Ptr elem;

Ptr QUE_head(queue)

QUE_Handle queue;

Ptr QUE_next(qelem)

Ptr qelem;

Ptr QUE_prev(qelem)

Ptr qelem;

Void QUE_insert(qelem, elem)

Ptr qelem;

Ptr elem;

Void QUE_remove(qelem)

Ptr qelem;

1 2 ... 196 197 198 199 200 201 202 203 204 205 206 ... 275 276

No comments

Coma FW-C2800 User's Guide Page 201