API GetNumDisplayChannels

channelCount = GetNumDisplayChannels()
This function returns the number of channels and headers currently displayed by ChannelFrame. Usually used to loop through all available channels/headers to perfom API GetChannelDisplayInfo on them.
Note that this function only retrieves the number of visible channels/headers! Those subchannels that are hidden by a collapsed header are not counted.
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This is part of the World of Warcraft API