RL-ARM - Determining priority of current task

I would like to briefly increase the priority of a currently running task and then revert the priority level.

The example given at:

www.keil.com/.../rlarm_os_tsk_prio_self.htm

shows how to do this.

void task1 (void) __task {
    .
    .
   os_tsk_prio_self(10);  /* Increase its priority, for the critical section */
    .                     /* This is a critical section */
    .
   os_tsk_prio_self(2);   /* Decrease its priority at end of critical section */
    .
    .
}

Trouble is, I would like to include this boost within a routine used by various tasks. I know at design time what level to boost to, but the level to return to would need to be determined at run time.

   OldPriority = CURRENT_TASK_PRIORITY_LEVEL;
    .
    .
   os_tsk_prio_self(10);
    .
    .
   os_tsk_prio_self(OldPriority);

I've looked for a function to determine the current task priority level, but cannot find one.

Anyone know of a way of doing this?