pSOSystem System Calls - Read

q_create pSOS+ System Calls
See Also
5. Q_LIMIT and a count equal 0 is a legitimate setting. This combination has the
interesting property that a q_send() will succeed only if there is already a task
waiting; otherwise, q_send() will fail.
6. Q_LIMIT set with Q_PRIBUF guarantees that enough buffers will be available
for messages to be posted at this queue. If Q_LIMIT is not set, then Q_PRIBUF
is ignored.
7. If a queue is created without private buffers, then messages posted to it will be
stored in buffers from the system-wide pool on the node where the queue
resides. The size of this pool is defined by the kc_nmsgbuf entry in the node's
pSOS+ Configuration Table.
8. The Q_GLOBAL attribute is ignored by the single-processor version of the pSOS+
kernel.
9. q_create() creates an ordinary message queue. Use q_vcreate() to create a
variable length message queue.
Multiprocessor Considerations
1. The Q_GLOBAL attribute should be set only if the queue must be made known to
other processor nodes in a multiprocessor configuration. If set, the queue's
name and qid are sent to the master node for entry in its Global Object Table.
2. If the Q_GLOBAL attribute is set and the number of global objects currently
exported by the node equals the Multiprocessor Configuration Table entry
mc_nglbobj, then the queue is not created and ERR_OBJTFULL is returned.
Callable From
■ Task
q_ident, q_delete, q_vcreate
1-76 pSOSystem System Calls