![]() udev-based systems should not need manual creation of such device entry. This device is needed to map the memory pool used by the shared queue into the caller's address space. -ENOENT is returned if the special file /dev/rtheap (character-mode, major 10, minor 254) is not available from the filesystem.Q_SHARED was not passed to rt_queue_create()). This error may also be returned whenever the call attempts to bind from a user-space application to a local queue defined from kernel space (i.e. interrupt, non-realtime or scheduler locked). -EPERM is returned if this service should block, but was called from a context which cannot sleep (e.g.-ETIMEDOUT is returned if the object cannot be retrieved within the specified amount of time.-EWOULDBLOCK is returned if timeout is equal to TM_NONBLOCK and the searched object is not registered on entry.-EINTR is returned if rt_task_unblock() has been called for the waiting task before the retrieval has completed.-EFAULT is returned if q or name is referencing invalid memory.Passing TM_NONBLOCK causes the service to return immediately without waiting if the object is not registered on entry. Passing TM_INFINITE causes the caller to block indefinitely until the object is registered. The number of clock ticks to wait for the registration to occur (see note). Contents of this memory is undefined upon failure. The address of a queue descriptor retrieved by the operation. Parameters:Ī valid NULL-terminated name which identifies the queue to bind to. If the queue does not exist on entry, this service blocks the caller until a queue of the given name is created. ![]() This user-space only service retrieves the uniform descriptor of a given shared Xenomai message queue identified by its symbolic name. Message buffer pools are built over the nucleus's heap objects, which in turn provide the needed support for exchanging messages between kernel and user-space using direct memory mapping. This implementation is based on a zero-copy scheme for message buffers. A message queue can be created by one task and used by multiple tasks that send and/or receive messages to the queue. Messages can vary in length and be assigned different types or usages. Message queueing is a method by which real-time tasks can exchange or pass data through a Xenomai-managed queue of messages. Rt_queue_bind (RT_QUEUE *q, const char *name, RTIME timeout) Rt_queue_inquire (RT_QUEUE *q, RT_QUEUE_INFO *info) Rt_queue_read (RT_QUEUE *q, void *buf, size_t size, RTIME timeout) Rt_queue_receive (RT_QUEUE *q, void **bufp, RTIME timeout) Rt_queue_write (RT_QUEUE *q, const void *buf, size_t size, int mode) Rt_queue_send (RT_QUEUE *q, void *mbuf, size_t size, int mode) Rt_queue_alloc (RT_QUEUE *q, size_t size) Rt_queue_create (RT_QUEUE *q, const char *name, size_t poolsize, size_t qlimit, int mode) I guess that some kind of semaphore needs to be used so that the execution of functions which manipulate the queue don't get mixed up.This file is part of the Xenomai project. enqueuing messages in an interrupt routine and dequeuing them on main. The queue and data sizes are defined as gave a good hint on how to structure the processing, i.e. The memory allocation for the queue can also be done as static variable instead of as stack variable. ![]() If necessary, the library functions used can easily be replaced with platform-specific versions or standard C array operations. The example given below should meet the requirements. "in a micro controller with a standard C you should manage the buffers, create the queue, enqueue and dequeue the elements" "example on how to create e message queue (like FIFO) of strings (or byte array) using standard C and how to manage the queue"
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