how to include git commit-number into a c++ executable?

Probably the easiest way to do this would be to add to your makefile a rule to generate a .c file with the current git commit ID:

gitversion.c: .git/HEAD .git/index    echo "const char *gitversion = \"$(shell git rev-parse HEAD)\";" > $@

Now simply add gitversion.c to your build process as normal. Make sure to remove it on make clean, and add it to .gitignore so it's not added to the git repository accidentally. Add an extern const char *gitversion; to a header somewhere, and you can access it like that.

I do the following in CMakeLists.txt:

IF(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/.git)  FIND_PACKAGE(Git)  IF(GIT_FOUND)    EXECUTE_PROCESS(      COMMAND ${GIT_EXECUTABLE} rev-parse --short HEAD      WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"      OUTPUT_VARIABLE "kml2maps_BUILD_VERSION"      ERROR_QUIET      OUTPUT_STRIP_TRAILING_WHITESPACE)    MESSAGE( STATUS "Git version: ${kml2maps_BUILD_VERSION}" )  ELSE(GIT_FOUND)    SET(kml2maps_BUILD_VERSION 0)  ENDIF(GIT_FOUND)ENDIF(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/.git)CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/kml2mapsVersion.h.in ${CMAKE_CURRENT_BINARY_DIR}/kml2mapsVersion.h @ONLY)

So the git rev-parse --short HEAD's output is good to build in the binary.

I use git describe to get a version which either uses a tag or commit number. This usually gives nice versions like: v0.1-1-g787c667 if the tip of the branch has additional commits above the 'v0.1' tag.

The git command I use is: git describe --tags --always. I usually use it with the SCons build system and define it as a constant, relevant parts of the SConstruct:

import os, sys from subprocess import *def getGitDesc():     return Popen('git describe --tags --always', stdout=PIPE, shell=True).stdout.read ().strip ()GIT_DESC = getGitDesc () print "Building " + getGitDesc () + ".." env = Environment ()# set up environment env.Append (CPPDEFINES = { 'GIT_DESC' : ('\\"%s\\"' % GIT_DESC) } )# build your programenv.Program (....)

In the C or C++ program I can now access GIT_DESC as a string-constant:

# include <iostream>using namespace std;int main (int argc, char ** argv) {  cout << "Version: " << GIT_DESC << endl;  return 42;}

note: the --abbrev=N argument to git describe might be useful to achieve consistent version output independent of a users git configuration.