pSOSystem System Calls - Read

q_vcreate pSOS+ System Calls
Return Value
Error Codes
Notes
qid Points to the variable where q_vcreate() stores the queue’s pSOSassigned
queue ID.
Queues created by q_vcreate() always have a fixed number of private buffers.
The pSOS+ kernel uses maxnum and maxlen to allocate sufficient memory for
message storage from region 0. If insufficient memory is available, an error is
returned. Queues created with q_vcreate() never allocate or use message buffers
from the pSOS+ message buffer pool.
This system call returns 0 on success, or an error code on failure.
Hex Mnemonic Description
0x08 ERR_OBJTFULL Node's object table full.
0x30 ERR_KISIZE Global queue maxlen too large for KI.
0x33 ERR_NOQCB Cannot allocate QCB; exceeds node's
maximum number of active queues.
0x34 ERR_NOMGB Not enough memory in region 0.
1. Internally, the pSOS+ kernel treats a queue name as a 32-bit integer. However,
when the application calls the kernel through the pSOS+ C language API, it
passes the queue name as a four-byte character array.
2. The pSOS+ kernel does not check for duplicate queue names. If duplicate
names exist, an q_vident() can return the qid of any queue with the
duplicate name.
3. The maximum number of queues that can be simultaneously active is defined
by the entry kc_nqcb in the pSOS+ Configuration Table. It applies to the
combined total of both fixed and variable queues.
4. The Q_GLOBAL attribute is ignored by the single-processor version of the pSOS+
kernel.
5. A special case occurs when maxnum is set to 0. In this case, a message can only
be successfully sent if a task is already waiting at the queue.
1-92 pSOSystem System Calls