Can CMake build subprojects (with benefits)?

Question

I have some huge project that is being compiled in CMake. It is developed for quite a long time, have 8000+ source/header files (over 500Mbytes, over 500 CMakefile.txt files).

They use directory structure like this

PROJECT_NAME
  src
    / subdir_name
    / other_dir_name
    / some_different_dir
    / MY_SPECIFIC_DIR             <---
    / yet_another_dir
   build

and build it out-source, like this:

name@host:~/PROJECT_NAME/build> cmake ../src
name@host:~/PROJECT_NAME/build> make all

then it's build as one BIG binary (details are not important).

---

I cannot touch anything else, just content of MY_SPECIFIC_DIR - it's source and CMake files. So, I have source code in MY_SPECIFIC_DIR tweak CMakefile.txt files somehow and would like to build it like this:

name@host:~/PROJECT_NAME/build_specific> cmake ../src/MY_SPECIFIC_DIR
name@host:~/PROJECT_NAME/build_specific> make all

This should build things in MY_SPECIFIC_DIR into single binary with some few links to other subprojects. But also (obviously) don't change anything about how whole project is compiled.

My question is:

Is my desired setup posible using CMake?
Can I somehow test in CMakeFile.txt that it is root project and build it in different way then when it is builded as a whole?

---

Unless, I have to resort to different means and use standard make for this. I don't know CMake so I'm hoping for YES/NO anwer, preferable even for technique how to achieve this. And then learn the CMake and do it.

Also, I must use CMake version 2.6.

Thanks

Answer 1

Basic concept is to use

if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   ... code for stand-alone app
else()
   ... what was in this file before
endif()