如何强制重新运行cmake，或通过CMakeLists.txt将功能添加到makefile

Question

I'd like to keep very close track of what version of my code I'm using for documentation purposes. Therefore I'd like to display the version of code I have compiled every time I run my program..

I've been using this previous question as reference.

How can I pass git SHA1 to compiler as definition using cmake?

I am using the two files that Ryan Pavlik suggested from his github repo, seen below: https://github.com/rpavlik/cmake-modules/blob/master/GetGitRevisionDescription.cmake.in#L13 https://github.com/rpavlik/cmake-modules/blob/master/GetGitRevisionDescription.cmake

And I have the following:

CMakeLists.txt

list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake/")
include(GetGitRevisionDescription)
get_git_head_revision(GIT_REFSPEC GITHASH)

set(test_GITHASH "\"${GITHASH}\"")

include_directories("${PROJECT_BINARY_DIR}")
configure_file ("${PROJECT_SOURCE_DIR}/testgithash.h.in"
                "${PROJECT_BINARY_DIR}/testgithash.h" )

testgithash.h.in

#define test_GITHASH @test_GITHASH@

So far I have my final executable displaying the hash from my testgithash.h file that is generated, but that header file is only refreshed when I run cmake . So really my question is, does anyone know of way that I can force cmake to re-run when I run make if my hash has changed? Or is there a way I can put the git hash functionality I'm looking for directly into my generated makefile rather than in my CMakeLists.txt?

Thanks in advance for any help!

Answer 1

As far as I've been able to figure out, the only way to force CMake to be rerun on some external condition is to have it include a file whose timestamp has been modified. Something like this:

# Somewhere in your CMakeLists.txt
include(external.stamp)

Then CMake will be rerun when external.stamp is updated.

In your case, maybe you could have a post-commit hook in git touch an (empty) file when a commit is made, then include that in your CMakeLists.txt .