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Installing pcl-cvs

If you don't normally deal with Emacs installation and site-maintenance issues, the pcl-cvs installation procedure may seem a bit daunting. A little background on how Emacs works may help.

Most higher-level Emacs features are written in a language called "Emacs Lisp" (Emacs itself is essentially an interpreter for this language). People add new features to Emacs by distributing files of Emacs Lisp code. pcl-cvs is written in this language, and it depends on a library of useful, generic Emacs Lisp functions called Elib (also written in part by Per Cederqvist, but distributed separately from pcl-cvs).

Elib is not included in the regular Emacs distribution (at least not FSF Emacs; I don't know about XEmacs), so you may have to download and install it yourself before you can use pcl-cvs. You can get it from Installation instructions are contained within the package.

Once Elib is installed, you're ready to build and install pcl-cvs. These instructions applies both to Version 1.05 and the 2.x series (although you should check the NEWS and INSTALL files in newer distributions to see what's changed).

First, unpack pcl-cvs (I'm using Version 1.05, but it could just as easily have been 2.9.6)

     floss$ zcat pcl-cvs-1.05.tar.gz | tar xvf -

and go into the source tree's top level:

     floss$ cd pcl-cvs-1.05/

A Makefile is supplied there. According to the instructions in the INSTALL file, you're supposed to edit a few paths at the top of the Makefile and then run:

     floss$ make install

If that works, great. However, this sometimes results in an error (the pcl-cvs code itself is very portable, but its installation procedures sometimes are not). Do this if you get an error:

     floss$ make clean
     floss$ make

If all goes well, these commands accomplish a significant part of the installation by byte-compiling all of the Emacs Lisp files. (Byte-compiling converts a file of human-readable Emacs Lisp code – an .el file – into a more compact and efficient representation – an .elc file. Emacs can load and run an .elc file with better performance than it can a plain .el file.)

I'll proceed as though the byte-compilation stage has succeeded. If the byte compilation does not appear to succeed, don't worry: The .elc files are a luxury, not a necessity. They improve performance slightly, but you can run pcl-cvs from the raw .el files with no problem.

If the make install failed, the next step is to get the Emacs Lisp (whether .el or .elc) into a directory where Emacs can load it automatically. Emacs has a designated directory on the system for locally installed Lisp. To find this directory – it will have a file named default.el in it – check the following locations, in this order:

  1. /usr/share/emacs/site-lisp/
  2. /usr/local/share/emacs/site-lisp/
  3. /usr/lib/emacs/site-lisp/
  4. /usr/local/lib/emacs/site-lisp/

Once you've found your site-lisp directory, copy all of the Lisp files to it (you may have to be root to do this):

     floss# cp -f *.el *.elc /usr/share/emacs/site-lisp/

The last step is to tell Emacs about the entry points to pcl-cvs (the main one being the function cvs-update), so it will know to load the pcl-cvs code on demand. Because Emacs always reads the default.el file when it starts up, that's where you need to list the pcl-cvs entry points.

Fortunately, pcl-cvs provides the necessary content for default.el. Simply put the contents of pcl-cvs-startup.el into default.el (or perhaps into your .emacs, if you're just installing this for yourself) and restart your Emacs.

You may also want to copy the .info files into your info tree and add pcl-cvs to the table of contents in the dir file.

Karl Fogel wrote this book. Buy a printed copy via his homepage at

copyright  ©  January 18 2019 sean dreilinger url: