Automatically store git hash inside C source

Sometimes we need to know what exact revision is a software. This doesn't work

#define VERSION 1.2

Just because it won't be updated by anyone.

On the other hand if using git, we could insert part of the revision hash automatically

• With a batch file
• Running the batch file from makefile in every build to avoid any manual task

Here is how

Edit makefile to insert code in build-pre section

	.build-pre:
	# Add your pre 'build' code here...
	version.bat
	$(info ************ RUNNING CUSTOM CODE FROM MAKEFILE ************)

view raw makefile hosted with ❤ by GitHub

Create the batch file version.bat to generate version.h with the hash constant inside

	@REM ---------------------------------------
	@REM This creates a .h with a macro VERSION
	@REM with part of the current git commit hash
	@REM
	@REM It should be called from Makefile
	@REM ---------------------------------------
	@ECHO OFF
	del version.h
	@ECHO ON
	@REM Shows description in build console
	git describe --always --abbrev=6 --dirty
	@ECHO OFF
	echo | set /p uglyName=#define VERSION >> version.h
	git describe --always --abbrev=6 --dirty >> tmpFile
	@set /p var= < tmpFile
	echo | set /p uglyName=""%var%"" >> version.h
	del tmpFile

view raw version.bat hosted with ❤ by GitHub

The automatic generated file will be something like this

#define VERSION "877bd1"

Wherever we need to use this version hash, this file must be included

#include "version.h"

Important

Add version.h to .gitignore to avoid modifying hash while build

Final Note

The git sha-1 hash will only acknowledge for changes in current project, if the code depends on other, the proper sha-1 code must be included (or a combination).

Reference and related info
This stackoverflow question