CODEWITHSUNDEEP
makefilecmake
Snooze7
Snooze7

Reputation: 9

including makefile while using cmake

need some help with using a 3rd party makefile when building my own project.

Upvotes: 0

Views: 3961

Answers (1)

nega
nega

Reputation: 2747

There isn't a way to what you want directly. CMake doesn't provide a facility to include files into its generated files. (ie: include a "3rdparty.mk" into a CMake generated Makefile.) Nor can you directly include a "generated-file-type" (ie: a Makefile) into a CMakeLists.txt. CMake's ExternalProject won't let you do that either.

What you need to do is somehow "parse" the makefile that has the information that you desire. There are a myriad of ways that you can do this. For example, you could write a shell-script wrapper that would grep your makefile for what you need then construct a CMake command line with the variables you want defined, and output it or call cmake for you. Depending on how comfortable you are with shell (or perl, python, etc.) you might feel this is the best option.

If you know these values will never (or very rarely change), you can hard code them in to your CMakeLists.txt (not recommended) or into a file you can include() (better).

You could also stay in CMake-land and use CMake's ExternalProject to help you. Using ExternalProject, you can:

  1. Fetch your 3rd party libraries (download, copy, unzip, etc)
  2. Patch the Makefiles of these libraries
  3. Run make on those patched makefiles

Now, this patch that I mentioned is something that you'd have to write yourself, and keep with the source of your primary project. The content of this patch would be a new target for make that would write a file that you could include in your CMakeLists.txt via include(). You could start simply, and have this new make target (eg: make output_variables) write a list of set() commands to lib_A.cmake. After comfortable with that, you could move on to more complicated output; like writing a lib_A-config.cmake file that CMake's find_package() would understand.

Granted, the last option is probably the most complicated but it might make maintenance of your primary project easier, reducing pain in the future. You'll also gain a deeper understanding of CMake.

Upvotes: 2

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