C.39. QUEUE_MEMBER_COUNT()

in Asterisk 1.4 - Asterisk 1.2 users see QUEUEAGENTCOUNT()
QUEUE_MEMBER_COUNT(queue)
Returns the number of agents (and/or members, which may be devices rather than logged-in users) in the specified queue.
; Number of members in "supportqueue":
exten => 123,1,Set(foo=${QUEUE_MEMBER_COUNT(supportqueue)}) 

Note

Internal help for this application in Asterisk 1.4:
  -= Info about function 'QUEUE_MEMBER_COUNT' =- 

[Syntax]
QUEUE_MEMBER_COUNT(<queuename>)

[Synopsis]
Count number of members answering a queue

[Description]
Returns the number of members currently associated with the specified queue.
diff output to internal help in Asterisk 1.2:
-- not available in Version 1.2 --