Adding Boost to CMake project?

Here's a working setup for Boost 1.68 with CMake 3.12. Boost 1.69 is apparently "too new" for cmake to detect it properly. Since boost is not buildable by cmake, cmake itself must provide a FindBoost.cmake module that must keep up with boost changes.

So anyway, the CMakeLists.txt is as small as this:

cmake_minimum_required(VERSION 3.11)

project(foobar)

find_package(Boost 1.68 REQUIRED)
add_executable(foo foo.cpp)
target_link_libraries(foo PUBLIC Boost::boost)

Of course, you can split it in many subdirectories.

Invoking CMake in the command line should look like this:

cmake -DCMAKE_PREFIX_PATH=path_to_local_directory ..

Where path_to_local_directory is the installation path of all library you want to depend on. It will work for Boost, nlohmann_json, glfw3, Qt, you name it *(1). For my case, it was C:/local/ and another case was ../external/ (yes, it can be a directory local to the project!)

Let's take a peek at my own C:/local/:

ls -l /c/local/
total 12
drwxr-xr-x 1 myself 197609 0 May 26  2018 boost_1_67_0/
drwxr-xr-x 1 myself 197609 0 Sep  5 02:02 boost_1_68_0/

WARNING: Ensure your compiler architecture is the same as the installed boost version. Or else cmake will simply not find it.

I think that about it. The next CMake version (3.14) should work with the latest boost.

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*(1) The said library will either need to export it's CMake target or you must provide a FindXXX.cmake

Following recipe should work

Download Boost binaries from official boost binaries location and install to say C:\Boost

Most times you do not need to build Boost on your own.

Your CMakeLists.txt should look like follows

cmake_minimum_required (VERSION 3.8)

project(boostAndCMake)

set(BOOST_ROOT "C:\Boost") # either set it here or from the command line  
set(Boost_USE_STATIC_LIBS OFF) 
set(Boost_USE_MULTITHREADED ON)  
set(Boost_USE_STATIC_RUNTIME OFF) 
find_package(Boost REQUIRED COMPONENTS system) # header only libraries must not be added here

add_executable(CMakeProject2 CMakeProject2.cpp CMakeProject2.h) 
target_include_directories(CMakeProject2 PUBLIC ${Boost_INCLUDE_DIRS}) 
target_link_libraries(CMakeProject2 ${Boost_LIBRARIES})

Because we used REQUIRED on the find_package call, CMake will fail execution and skip the rest of the script if it cannot be found. So no need to check Boost_FOUND. You need to check it, when you omit REQUIRED.

Now from the command line call from the directory where your script resides:

cmake -H. -Bbuildit -G "Visual Studio 15 2017" -DBOOST_ROOT=C:\Boost 

This creates a build directory named buildit in the current directory, further creates a solution for Visual Studio 2017 inside the build directory and provides the setting for the variable BOOST_ROOT that is used in the find_package call to identify the Boost directory on your computer. To see what options are available on the find_package(Boost ...) call see FindBoost documentation in CMake.

Header Only Libraries

If your libraries are header only you need to omit them from the find_package(Boost ...) call. To see which libraries are not header only see this post.

Using newer Boost versions

If your CMake installation cannot find the requested version, e.g. 1.69.0, but supports the naming scheme of the more recent Boost version you can use it with set(Boost_ADDITIONAL_VERSIONS "1.69.0" "1.69"). Last change of the Boost naming scheme was from 1.65.1 to 1.66.