Synopsis:
   $iscurchan(<channel name>)

Technical:
   This function returns '1' if the input channel name is the current channel
   on any window connected to the current server.

Practical:
   This function was intended to allow more flexibility for testing the
   current channel in an ON hook.

Returns:
   '1' if <channel name> is a current channel, else returns '0'

Examples:
   Instead of:
      /on ^send_public * {if ([$0] == C) {...} {...}}
   Try doing:
      /on ^send_public * {if (iscurchan($0)) {....} {...}}