Platform independent builds with Cmake

October 10, 2019

A wide variety of programming languages are used by engineers and scientists. Tie them all together (C, C++, C#, Cuda, Fortran, etc.) in a platform-independent and simple way using CMake or Meson. These high-level build systems generate low-level build system backend files for Ninja (strongly recommended) or Make.

Assume a single-file C++ program that uses the Math library and Boost for flexible command-line input of numerous parameters. Turn on additional compiler warnings to help avoid common coding pitfalls. Consider an example CMakeLists.txt for a C++ and Fortran project, line by line.

Language(s) selection:

project(zakharov CXX)

Naming a project facilitates packaging and installation. CXX is required to enable the hooks for the language(s) you used. The most frequently used languages include

tag	language
C	C
C#	C#
CXX	C++
Fortran	Fortran

Languages that aren’t built into Cmake such as Pascal can be added via custom Cmake modules.

Compiler options:

if(CMAKE_Fortran_COMPILER_ID STREQUAL "GNU")
  add_compile_options(-mtune=native -Wall -Wextra -Wpedantic -fexceptions -Warray-bounds)
endif()

-mtune=native: use specialized optimizations for your particular CPU
-Wall -Wextra -Wpedantic -Warray-bounds: turn on warnings for common programming mistakes
-fexceptions: more detailed debug info with no speed penalty–enabled by default on Clang.

find_package(Boost REQUIRED COMPONENTS filesystem program_options)

We use Boost:

filesystem: directory manipulation
program-options: advanced command-line parsing

add_executable(zakh zakh.cpp)
target_link_libraries(zakh PRIVATE Boost::filesystem Boost::program_options)
target_compile_features(modules PRIVATE cxx_std_11)

This project requires C++11 features, so an old compiler not supporting C++11 will emit a configuration error.

zakh: the exe file that will be created on compile, run with ./zakh.
zakh.cpp: the files making up “zakh”

Compiling a simple project with CMake: It’s convenient to create a separate directory, typically build/ under your main code directory. Let’s say your main code directory is ~/code/zakharov, then do

# configure
cmake -B build/`

# build program
cmake --build build/ --parallel

# run program
./zakh

Let’s say you edit the code–rebuild and run by:

cmake --build build/ --parallel

./zakh

Normally you do not need to reconfigure CMake if just editing source code.

CMake alternatives include Meson.