critcl_install_guide(3) The Installer's Guide


Welcome to the C Runtime In Tcl, CriTcl for short, a system to build C extension packages for Tcl on the fly, from C code embedded within Tcl scripts, for all who wish to make their code go faster.

The audience of this document is anyone wishing to build the packages, for either themselves, or others.

For a developer intending to extend or modify the packages we additionally provide

Critcl - License.
Critcl - The Developer's Guide.

Please read Critcl - How To Get The Sources first, if that was not done already. Here we assume that the sources are already available in a directory of your choice.


Before Critcl can be build and used a number of requisites must be installed. These are:
The scripting language Tcl. For details see Tcl.
Various packages from the Tcllib bundle for Tcl. For details see Tcllib.

This list assumes that the machine where Critcl is to be installed is essentially clean. Of course, if parts of the dependencies listed below are already installed the associated steps can be skipped. It is still recommended to read their sections though, to validate that the dependencies they talk about are indeed installed.


As we are building a Tcl package that should be pretty much obvious that a working Tcl installation is needed, and I will not belabor the point.

Out of the many use whatever you are comfortable with, as long as it provides Tcl 8.5, or higher, and Tk 8.5 or higher.

This may a Tcl installation provided by your operating system distribution, from a distribution-independent vendor, or built by yurself.

Myself, I used ActiveState's [] ActiveTcl 8.5 distribution during development of the binding, as I am most familiar with it.

(Disclosure: I, Andreas Kupries, work for ActiveState, maintaining ActiveTcl and TclDevKit for them).

This distribution can be found at Retrieve the archive of ActiveTcl 8.5 for your platform and install it as directed by ActiveState.

Assuming that ActiveTcl got installed I usually run the command

    teacup update
to install all packages ActiveState provides, and the kitchensink, as the distribution itself usually contains only the ost important set of packages. This ensures that the dependencies for Critcl are all present, and more.

If that is not to your liking you have to read the sections for Critcl to determine the exact set of packages required, and install only these using

    teacup install $packagename

Both teacup commands above assume that ActiveState's TEApot repository at is in the list of repositories accessible to teacup. This is automatically ensured for the ActiveTcl distribution. Others may have to run

    teacup archive add

to make this happen.

For those wishing to build Tcl/Tk on their own, their sources can be found at



To use Critcl a few packages found in the Tcllib bundle are required. These packages are:

And to accelerate this package, it is recommend to get and install one of

The system will work without them, but can become quite slow, especially when handling large code blocks.

Assuming that ActiveTcl is installed, or some other Tcl installation with teacup available, most (not md5c) of these packages can be installed via

    teacup install $packagename

The teacup command above assumes that ActiveState's TEApot repository at is in the list of repositories accessible to teacup. This is automatically ensured for the ActiveTcl distribution. Others may have to run

    teacup archive add

to make this happen.

Now, for those wishing to install the packages from source, the CVS repository for the two bundles can be found at

Releases of Tcllib can be found in the associated Files section, or CVS can be used to check out the sub-project tcllib.

Tcllib comes with its own installation instructions. These will not be repeated here. If there are problems with its directions please file a bug against the Tcllib project at the above url, and not Critcl.


To install Critcl simply run
    /path/to/tclsh /path/to/critcl/build.tcl install
where "/path/to/tclsh" is the tclsh of your Tcl installation, and "/path/to/critcl" the location of the Critcl sources on your system.

This builds all packages and then places them in a directory where the tclsh will find them.

It further creates a "critcl" application script and places it into the directory tclsh resides in, making it a sibling of that executable. The critcl application is written to use that executable as well, and not search for it in the PATH.

On Windows you can invoke the file "build.tcl" with a double-click. This will pop up a small graphical interface for entering the destination and performing the installation. This handling of a double-click is restricted to Windows only however.

On unix the same GUI is acessible by invoking "build.tcl" without any arguments.

To get help about the methods of "build.tcl", and their complete syntax, invoke "build.tcl" with argument help, i.e., like

    /path/to/tclsh /path/to/critcl/build.tcl help


With critcl installed it is now the time to try at least one of the examples distributed with it. This will also test if the installation was successful.

Below I show the steps to generate and then use the low- and high-level stack example packages. I am intentionally bypassing the "build.tcl" file the example is coming with, to show the use of critcl itself.

    > cd examples/stack
    > /path/to/critcl -keep -cache B -pkg cstack.tcl
    > /path/to/critcl -keep -cache B -pkg stackc.tcl
    > tclsh
    % lappend auto_path [pwd]/lib
    % package require stackc
    % join [info loaded] \n
    % stackc S
    % S push FOO
    % S size
    % S destroy
    % exit

Some explanations:

  • The example shows only the commands entered on the shell (and tclsh) command line. Their responses are left out.
  • Use of option -keep causes critcl to leave the generated .c files behind, for edification. Normally this happens only in case of trouble.
  • Use of option -cache redirects the location of the directory to hold generated and build files to a local directory with a known name, for an easy look after.
  • Both cstack and stackc have to use the same -cache so that stackc will find the stub table headers exported by cstack.


Jean Claude Wippler, Steve Landers, Andreas Kupries


This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report them at Ideas for enhancements you may have for either package, application, and/or the documentation are also very welcome and should be reported at as well.


C code, Embedded C Code, code generator, compile & run, compiler, dynamic code generation, dynamic compilation, generate package, linker, on demand compilation, on-the-fly compilation


Glueing/Embedded C code


Copyright (c) Jean-Claude Wippler
Copyright (c) Steve Landers
Copyright (c) 2011-2013 Andreas Kupries