Overview
========

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


Known variations from pSOS
==========================

You may observe some variations from pSOS. 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:

- pSOS task priorities are restricted to [1..97] in the current
  implementation of the emulator.

- Clearing the T_SLICE bit using t_mode() may induce a round-robin
  effect within the priority level of the current task.

- T_LEVELMASKx bits are ignored by the emulator
  (e.g. t_mode()). Interrupts are always enabled for the running task.

- The following calls may return ERR_SSFN when called from a
  non-pSOS task context:

  ev_receive, tm_evafter, tm_evevery, tm_evwhen

- ERR_NOTIME is never returned, since the emulator sets the pSOS time
  at startup.

- q_create() always uses system buffers (Q_SYSBUF), regardless of the
  creation flags (i.e. Q_PRIBUF is ignored). System buffer memory is
  only limited by the addressable process memory; it is obtained from
  the main memory pool (see --mem-pool-size init option).

- Fixed and variable size message queues share a common namespace with
  respect to q_[v]ident() calls.

- tm_set() will not elapse any outstanding timer based on calendar
  time which timeout date moves to the past as a consequence of this
  call.

- rn_retseg() does not fully check the validity of the pointer
  argument. Therefore ERR_SEGADDR and ERR_SEGFREE error codes will
  never be returned, and passing a non-NULL invalid pointer within the
  bounds of the region may lead to unpredictable results.

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