Which api's can be invoked from an isr?

[Scott J]

Hi, all
    I'm now so clear about which api's could be invoked from an isr. For example, in a timer service, I know it is part of rtems_clock_tick() which is the timer isr in general, can I call rtems_task_start()? There is a list of system calls which can be called from an isr in RTEMS C User' Guide, but only a few functions listed there. So it is dangerous if I did call functions not listed there?
	Thanks for anyone helps.
	
PS. I find message_queue_send() and message_queue_urgent() are listed there but message_queue_broadcast() not. I'm confused somewhat. :-p

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Scott