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 wh

Answer 1

See wiki page on versioning with make

Answer 2

Add this to configure.ac:

AM_CONDITIONAL([IS_HG_REPO], [test -d "$srcdir/.hg"])

Add the following lines to Makefile.am:

if IS_HG_REPO
AM_CPPFLAGS = -DHGVERSION="\"$(PACKAGE) `hg parents --template 'hgid: {node|short}'`\""
else
AM_CPPFLAGS = -DHGVERSION=PACKAGE_STRING
endif

This will define HGVERSION as a string of the form APPNAME hgid: 24d0921ee4bd or APPNAME VERSION, if building from a release tarball.

Answer 3

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]), 
  [bug-autoconf@gnu.org])

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.