Selecting Homebrew version of Tk on macOS

[poldy]

On macOS, when I installed using "opam install labltk" this linked against Apple's version of Tk which honestly isn't very good.

To use the better version I installed using "brew install tcl-tk", I had to run "opam uninstall labltk" again (which probably left its dependencies in place), then the following commands in a git clone of this repo (these are a slightly-extended version of what "opam show --raw labltk" gave):

./configure -use-findlib -verbose -installbindir $HOME/.opam/5.0.0+flambda/bin -tkdefs -I/opt/homebrew/opt/tcl-tk/include -tklibs -L/opt/homebrew/opt/tcl-tk/lib -tk-no-x11
make library opt
make install

This worked, but I was wondering if there was a nicer way to do this with some options to opam?

If it helps, you can set PKG_CONFIG_PATH=/opt/homebrew/opt/tcl-tk/lib/pkgconfig:$PKG_CONFIG_PATH then pkg-config --cflags tk gives the required value for -tkdefs above; and pkg-config --libs tk give the equivalent of LDFLAGS in make (i.e. library search directory for -tklibs and required libraries).

[mtoups3]

Update: now that Tcl/Tk 9.0 is out, the configure line given here does not work. Also, the configure script can't detect this version, as discussed here: #27 (comment) and #28 (comment)

This configure line did work for me on macOS 14.x and 26.0.1:

./configure -use-findlib -tkdefs -I/opt/homebrew/opt/tcl-tk/include/tcl-tk -tklibs '-L/opt/homebrew/opt/tcl-tk/lib -ltcl9tk9.0 -ltkstub -ltcl9.0 -ltclstub'

the line above works on ARM CPUs (so-called Apple Silicon, M1/M2/M3/M4 chips)

For older Intel CPUs, homebrew installs into a different location. This should work instead:

./configure -use-findlib -tkdefs -I/usr/local/opt/tcl-tk/include/tcl-tk -tklibs '-L/usr/local/opt/tcl-tk/lib -ltcl9tk9.0 -ltkstub -ltcl9.0 -ltclsub'

I hope in the future the configure script can detect the homebrew tcl-tk - but for now these workarounds might help folks.