Overview
========

This directory contains a VxWorks(*) emulation interface on top of the
Xenomai framework.

Known variations from VxWorks/WIND
==================================

You may observe some variations from VxWorks. If you find such a
variation and you think it would be easy to correct, please mail to
the Xenomai mailing list at <xenomai@xenomai.org>.  Here are the known
variations:

- VxWorks task priorities are restricted to [97..0] in the current
  implementation of the emulator.

- taskInit() does not allow to create unnamed tasks, but assigns an
  auto-generated name like taskSpawn() whenever a NULL or empty name
  string is given.

- taskUnlock() may induce a round-robin effect within the priority
  level of the task releasing the scheduler lock.

- semDelete() does not flush a mutex semaphore. May return
  S_semLib_INVALID_OPERATION if busy upon deletion.

- semMCreate() does not support FIFO queuing mode, but only PRIO.

- semTake() will complain about the owner of a mutex-type semaphore
  exiting without releasing the lock while the current task pends on
  it. S_objLib_OBJ_UNAVAILABLE is then returned to the caller, and the
  semaphore is left in an inconsistent state.

- kernelInit() has a different signature than the original WIND kernel
  call, i.e.:
  STATUS kernelInit(FUNCPTR rootRtn, int argc, char *const argv[]).

  The first argument is a pointer to an optional root task entry
  point, which the emulator will name "rootTask", and start with
  priority 50. Since kernelInit() is usually called on behalf of a non
  real-time thread within the application's main() routine, the root
  task will preempt the caller immediately. If NULL is passed, no root
  task will be started by kernelInit().

  The second and third arguments should be the argument count and
  vector, as passed to the application's main() routine on the
  command line. Passing 0/NULL is valid, meaning that no command line
  argument may be used to override the default emulator settings.

- memPartCreate() may return S_memLib_NOT_ENOUGH_MEMORY in case a
  memory shortage happens while allocating the internal partition
  descriptor. I.e. this descriptor is not laid into the user-provided
  memory.

- memPartAddToPool() may return S_objLib_OBJ_ID_ERROR when called with
  an invalid partition identifier.

- The following calls may return S_objLib_OBJ_NO_METHOD when called
  from a non-VxWorks task context:

  taskDelay, taskLock, taskUnlock, taskSafe, taskUnsafe, and taskIdSelf.


(*) VxWorks is a registered trademark of Wind River Systems, Inc
(http://www.windriver.com).