taskvariableget.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

/*
 *  rtems_task_variable_get - Get a per-task variable
 *
 *
 *  COPYRIGHT (c) 1989-1999.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.com/license/LICENSE.
 *
 *  $Id: taskvariableget.c,v 1.2.4.2 2004/05/06 19:20:04 joel Exp $
 */

#include <rtems/system.h>
#include <rtems/rtems/tasks.h>
#include <rtems/score/wkspace.h>

/*
 *  rtems_task_variable_get
 *
 *  This directive gets the value of a task variable. 
 */

rtems_status_code rtems_task_variable_get(
  rtems_id tid,
  void **ptr,
  void **result
)
{
  Thread_Control        *the_thread;
  Objects_Locations      location;
  rtems_task_variable_t *tvp;

  if ( !ptr )
    return RTEMS_INVALID_ADDRESS;

  if ( !result )
    return RTEMS_INVALID_ADDRESS;

  the_thread = _Thread_Get (tid, &location);
  switch (location) {
  case OBJECTS_REMOTE:
#if defined(RTEMS_MULTIPROCESSING)
    _Thread_Dispatch();
    return RTEMS_ILLEGAL_ON_REMOTE_OBJECT;
#endif

  case OBJECTS_ERROR:
    return RTEMS_INVALID_ID;

  default:
    return RTEMS_INTERNAL_ERROR;

  case OBJECTS_LOCAL:

    /*
     *  Figure out if the variable is in this task's list.
     */

    tvp = the_thread->task_variables;
    while (tvp) {
      if (tvp->ptr == ptr) {
	/*
	 * Should this return the current (i.e not the
	 * saved) value if `tid' is the current task?
	 */
        *result = tvp->tval;
        _Thread_Enable_dispatch();
        return RTEMS_SUCCESSFUL;
      }
      tvp = tvp->next;
    }
    _Thread_Enable_dispatch();
    return RTEMS_INVALID_ADDRESS;
  }
  return RTEMS_INTERNAL_ERROR;   /* unreached - only to remove warnings */
}