The Ports Collection supports parallel installation of multiple Tcl/Tk versions. Ports should try to support at least the default Tcl/Tk version and higher with the USE_TCL and USE_TK variables. It is possible to specify the desired version of tcl with the WITH_TCL_VER variable.
Table 6-22. The Most Useful Variables for Ports That Use Tcl/Tk
| USE_TCL | The port depends on the Tcl library (not the shell). Minimal required version can be specified with values such as 84+. Individual unsupported versions can be specified with the INVALID_TCL_VER variable. |
| USE_TCL_BUILD | The port needs Tcl only during the build time. |
| USE_TCL_WRAPPER | Ports that require the Tcl shell and do not require a specific tclsh version should use this new variable. The tclsh wrapper is installed on the system. The user can specify the desired tcl shell to use. |
| WITH_TCL_VER | User-defined variable that sets the desired Tcl version. |
| UNIQUENAME_WITH_TCL_VER | Like WITH_TCL_VER, but per-port. |
| USE_TCL_THREADS | Require a threaded build of Tcl/Tk. |
| USE_TK | The port depends on the Tk library (not the wish shell). Implies USE_TCL with the same value. For more information see the description of USE_TCL variable. |
| USE_TK_BUILD | Analog to the USE_TCL_BUILD variable. |
| USE_TK_WRAPPER | Analog to the USE_TCL_WRAPPER variable. |
| WITH_TK_VER | Analog to the WITH_TCL_VER variable and implies WITH_TCL_VER of the same value. |
A complete list of available variables can be found in /usr/ports/Mk/bsd.tcl.mk.