CODEWITHSUNDEEP
gitmakefileautotools
yolenoyer
yolenoyer

Reputation: 9445

Displaying from which git commit a binary was compiled

I'm using autotools and git in a C/C++ program.

I would like my program to be able to show from which commit it was compiled. For example it would show:

$ myprog --version
Binary compiled from commit 9ddb505

In bash, it's easy to determine the current commit:

COMMIT=$(git log -1 --pretty='%h')

But this syntax is not valid inside a Makefile.am file.

Let's say I have a very simple Makefile.am:

bin_PROGRAMS = myprog
myprog_SOURCES = main.c
myprog_CPPFLAGS = -Wall -DGIT_COMMIT=\"??SOMETHING??\"

How can I pass the right commit value to my source, considering that the commit name must be up-to-date on each call of make?

EDIT

I tried also (in Makefile.am):

COMMIT=\"$(shell git log -1 --pretty='%h')\"

But this syntax generate an error with automake:

src/Makefile.am:3: warning: shell git log -1 --pretty='%h': non-POSIX variable name src/Makefile.am:3: (probably a GNU make extension)

, and it's colored in red with Vim's syntax (filetype=automake).

The solution would be to pass directly this line to be included in the final Makefile, but how can I do this in Makefile.am? I tried to escape the $ sign, with no success.

Upvotes: 3

Views: 1258

Answers (3)

Angelo Dureghello
Angelo Dureghello

Reputation: 330

Use this in Makefile.am

AM_CXXFLAGS = -DGIT_VERSION="\"$(shell git log -1 --pretty='%h')\""

You will still get the warning

Makefile.am:14: warning: shell git log -1 --pretty='%h': non-POSIX variable name
Makefile.am:14: (probably a GNU make extension)

Make it disappear with:

AM_INIT_AUTOMAKE(-Wno-portability)

in configure.am

Upvotes: 0

G.Pei
G.Pei

Reputation: 101

I think for you the missing link appears to be the shell cmd in Make.

You can do in your Makefile:

GIT_MSG=\"$(shell git log -1 --pretty='%h')\"
CFLAGS=-Wall -DGIT_COMMIT=$(GIT_MSG)

Then use GIT_COMMIT as a macro in your C/C++ source files.

P.s.:

Use the following for something like master-1399ff4:

GIT_MSG=\"$(shell echo "`git symbolic-ref HEAD 2> /dev/null | cut -b 12-`-`git log --pretty=format:\"%h\" -1`, ")\"

And use git describe to print tags if your git repo has any.

Upvotes: 1

Lazy Badger
Lazy Badger

Reputation: 97282

Add

GITVERSION:= $(shell git log -1 --pretty='%h')

to your Makefile and

-DGITVERSION="\"${GITVERSION}\""

to your CPPFLAGS and you can use GITVERSION inside code

Upvotes: 1

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