Question

I have C++ project using cmake. I’d like to have versioning (in meaning of provide unique ./myapp --version output) based on git commits. Manually it’s something like

gcc ... -DVERSION=$(git rev-list|wc -l)

and using VERSION macro if defined in code.

This works as expected. But how should I write it into CMakeLists.txt (let’s use echo for simplicity)? How should I escape it?

add_definitions(-DVERSION="$(echo 1)")

Answer 1

In cmake 2.8.8 you can:

add_definitions(demo -D`echo VERSION=\\`git rev-list HEAD|wc -l\\``)

and:

int main(int argc, char *argv[]) {
  printf("Version: %d", VERSION);

To compile as:

/usr/bin/gcc   -std=c99 demo -D`echo VERSION=\`git rev-list HEAD|wc -l\`` -o CMakeFiles/demo.dir/src/demo.c.o   -c /home/doug/projects/libar/src/demo.c

And results in:

build$ ./demo
Version: 88

This seems to be what you actually want.