How do I add revision and build date to source?

I have a GCC project and would like to automatically add defines for build date and revision number (f开发者_StackOverflow社区rom git) to my sources. What's the best way to do this?

My goal is simple to be able to do something like this on startup:

printf("Test app build on %s, revision %d", BUILD_DATE, REVISION)

For building I'm using make with a simple Makefile.inc, not autoconf or anything like this.

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I ended up using a simple command like this in my Makefile:

echo "#define GIT_REF \"`git show-ref refs/heads/master | cut -d " " -f 1 | cut -c 31-40`\"" > git_ref.h

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RCS keyword substitution is not natively supported by Git, but can be added with a gitattributes filter driver: See "Git equivalent of subversion's $URL$ keyword expansion".

For example (not exactly relate to your question, but illustrates the general principle):

git config filter.rcs-keyword.clean 'perl -pe "s/\\\$Date[^\\\$]*\\\$/\\\$Date\\\$/"'
git config filter.rcs-keyword.smudge 'perl -pe "s/\\\$Date[^\\\$]*\\\$/\\\$Date: `date`\\\$/"'

You will base your filter script on the result of git describe --tags called from your Makefile.

As mentioned in this answer to "Git equivalent of subversion's $URL$ keyword expansion", smudge/clear filter driver is not a perfect solution, and adding any kind of meta-data directly in the data (source) is generally a bad idea (you have a debate about it in "What are the basic clearcase concepts every developer should know?").

Yet you have a good example of such Git keyword expansion in this answer in "How do I enable ident string for Git repos?".