The Tcl/Tk documentation is in windows the directory ‘R_HOME/Tcl/doc’. unix the system man pages.
For a complete list of functions, use ls("package:tcltk").
unix
Note that Tk will not be initialized if there is no DISPLAY
variable set, but Tcl can still be used. This is most useful to allow
the loading of a package which depends on tcltk in a session that
does not actually use it (e.g., during installation).