$ischanvoice(<nick> <channel>)

This function searches the client's channel cache for the user <nick> on the channel <channel> for the current server refnum, and returns their current channel voiced status.

   1   User has voice (is +v)
   0   User does not have voice (is not +v)
  -1   Client does not know (may or may not be +v)

Voiced information is given by the server in the names reply that is sent on join and also in the who reply that epic asks for.

Unfortunately, most servers will not divulge the voiced status of a user if they are also a channel operator (+o).

Consequently, unless you are physically present when a +v or -v mode change occurs, there is no way for epic to know whether or not a channel operator is voiced or not.

Therefore, the client will return the “I don't know” value (-1) if you ask it for the voiced status of anyone who was a channel operator when you joined the channel.