Injecting mercurial changeset as version information in a C executable

Question

I would like the executables for a project I am working on to have the latest mercurial changeset recorded so that when a user complains about buggy behavior, I can track which version they are using. Some of my executables are Python and others are compiled C. Is there a way to automate this, or can you point me to projects that exhibit solutions that I can look at?

I am using autoconf in my project... in case that makes the solution easier.

Thanks!

Setjmp

Answer 1

A common way to do this is with m4_esyscmd. For example, autoconf distributes a script in build-aux which generates a version number from the git repo and invokes AC_INIT as:

AC_INIT([GNU Autoconf], m4_esyscmd([build-aux/git-version-gen .tarball-version]), 
  [[email protected]])

You can often get away without distributing the script and do something simple like:

AC_INIT([Package name], m4_esyscmd([git describe --dirty | tr -d '\012']), 
  [bug-report-address])

Instead of git-describe, use whatever command you want to generate the version number. One important detail is that it should not have a trailing newline (hence the tr following git-describe).

A major drawback with this technique is that the version number is only generated when you run autoconf.