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kernel: msg_q: k_msgq_peek() implementation

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Add implementation for k_msgq_peek() which is similar to k_msgq_get()
except the message is not deleted from the queue.

Signed-off-by: Sathish Kuttan <sathish.k.kuttan@intel.com>
This commit is contained in:
Sathish Kuttan 2018-11-09 21:04:36 -08:00 committed by Anas Nashif
parent 3efd8e17bd
commit a8aa235d9b
1 changed files with 31 additions and 0 deletions
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31
kernel/msg_q.c
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@ -245,6 +245,37 @@ Z_SYSCALL_HANDLER(k_msgq_get, msgq_p, data, timeout)
}
#endif
int _impl_k_msgq_peek(struct k_msgq *q, void *data)
{
unsigned int key = irq_lock();
int result;
if (q->used_msgs > 0) {
/* take first available message from queue */
(void)memcpy(data, q->read_ptr, q->msg_size);
result = 0;
} else {
/* don't wait for a message to become available */
result = -ENOMSG;
}
irq_unlock(key);
return result;
}
#ifdef CONFIG_USERSPACE
Z_SYSCALL_HANDLER(k_msgq_peek, msgq_p, data)
{
struct k_msgq *q = (struct k_msgq *)msgq_p;
Z_OOPS(Z_SYSCALL_OBJ(q, K_OBJ_MSGQ));
Z_OOPS(Z_SYSCALL_MEMORY_WRITE(data, q->msg_size));
return _impl_k_msgq_peek(q, (void *)data);
}
#endif
void _impl_k_msgq_purge(struct k_msgq *q)
{
unsigned int key = irq_lock();