How about forking off the IRC component, and employing some form of IPC to hand data back and forth? The IRC gizmo can write to the parent through a pipe, and the parent can know about it through a Tk::fileevent. If the parent writes to the child, the kid can listen with the same select loop that reads the IRC stream.

Even without fork, the Tk::fileevent can be connected to the IRC socket to produce event-oriented actions.