Convert from Xcode to CMake

Question

I have a C++ project that I initially developed using Xcode on my Mac and I would like to set up the very same project using CMake. The project makes use of some external libraries, including eigen and boost. Xcode has a rather long list of Build Settings, including paths to external libraries, specification of the compiler version, additional linker flags, compiler optimization level, etc... and I am wondering where all of this information goes in the CMakeLists.txt file. I've searched extensively for help on this but have found precious little. I am new to CMake and have never written make files before. If there were a utility that could convert my Xcode project into a CMake project, that would be ideal. But I would be very glad to know of a tutorial on this, or to have some specific guidance. Any help on this would be greatly appreciated.

Answer 1

Conversion Strategy

I am pretty sure that the easiest and fastest way to move to CMake is a mixture of looking at comparable projects that link the same dependencies, and maybe copying a few relative file paths to your source files from XCode. A well-written CMakeLists.txt that uses Eigen and Boost can be very small (and platform-independent).

One reason for this is CMake has a very different way to use dependencies. For well-known libraries such as Boost, CMake includes scripts to include headers and link libraries.

Minimal CMakeLists.txt

A minimal example may look like this:

find_package(Eigen3 REQUIRED)
find_package(Boost REQUIRED COMPONENTS system)
add_executable(
  app
  src/main.cpp
)
target_include_directories(
  app
  ${Eigen3_INCLUDE_DIRS}
  ${Boost_INCLUDE_DIR}
)
target_link_libraries(
  app
  ${Boost_LIBRARIES}
)

Example Projects

For Eigen, there is no such pre-installed script that can be called by find_package. Here are two real-world example projects that link Eigen and Boost: https://github.com/ompl/ompl/blob/master/CMakeLists.txt https://github.com/roboticslibrary/rl

Here is an example for a find script for Eigen.

As a piece of advice, some CMake projects are out there are convoluted and use old syntax, newer project files tend to use small letters in commands.