Sampleextension is the "official" example of a extension. Write some C functions, and then follow the example to add the required autogoo to get it to compile as an extension.
The Tcl sample extension implements an extension calculating the Core Secure Hash Algorithm (sha1). It demonstrates a TEA-conformant Tcl extension that includes a C library that can be dynamically loaded. It also illustrates the TEA directory structure and use of Tcl autoconf extensions to to provide configure and make facilities.
# Replace quux with the name of your extension EXTNAME=quux wget -qO- http://core.tcl.tk/sampleextension/tarball/${EXTNAME}.tar.gz | tar xzv cd ${EXTNAME} wget -qO- http://core.tcl.tk/tclconfig/tarball/tclconfig.tar.gz | tar xzv # Write your source files # Edit configure.in autoconf # And then the usual: ./configure make