[c++] Difference between using Makefile and CMake to compile the code

I code on C/C++ and use a (GNU) Makefile to compile the code. I can do the same with CMake and get a MakeFile. However, what is the difference between using Makefile and CMake to compile the code?

This question is related to c++ c makefile cmake

The answer is


The statement about CMake being a "build generator" is a common misconception.

It's not technically wrong; it just describes HOW it works, but not WHAT it does.

In the context of the question, they do the same thing: take a bunch of C/C++ files and turn them into a binary.

So, what is the real difference?

  • CMake is much more high-level. It's tailored to compile C++, for which you write much less build code, but can be also used for general purpose build. make has some built-in C/C++ rules as well, but they are useless at best.

  • CMake does a two-step build: it generates a low-level build script in ninja or make or many other generators, and then you run it. All the shell script pieces that are normally piled into Makefile are only executed at the generation stage. Thus, CMake build can be orders of magnitude faster.

  • The grammar of CMake is much easier to support for external tools than make's.

  • Once make builds an artifact, it forgets how it was built. What sources it was built from, what compiler flags? CMake tracks it, make leaves it up to you. If one of library sources was removed since the previous version of Makefile, make won't rebuild it.

  • Modern CMake (starting with version 3.something) works in terms of dependencies between "targets". A target is still a single output file, but it can have transitive ("public"/"interface" in CMake terms) dependencies. These transitive dependencies can be exposed to or hidden from the dependent packages. CMake will manage directories for you. With make, you're stuck on a file-by-file and manage-directories-by-hand level.

You could code up something in make using intermediate files to cover the last two gaps, but you're on your own. make does contain a Turing complete language (even two, sometimes three counting Guile); the first two are horrible and the Guile is practically never used.

To be honest, this is what CMake and make have in common -- their languages are pretty horrible. Here's what comes to mind:

  • They have no user-defined types;
  • CMake has three data types: string, list, and a target with properties. make has one: string;
  • you normally pass arguments to functions by setting global variables.
    • This is partially dealt with in modern CMake - you can set a target's properties: set_property(TARGET helloworld APPEND PROPERTY INCLUDE_DIRECTORIES "${CMAKE_CURRENT_SOURCE_DIR}");
  • referring to an undefined variable is silently ignored by default;

Examples related to c++

Method Call Chaining; returning a pointer vs a reference? How can I tell if an algorithm is efficient? Difference between opening a file in binary vs text How can compare-and-swap be used for a wait-free mutual exclusion for any shared data structure? Install Qt on Ubuntu #include errors detected in vscode Cannot open include file: 'stdio.h' - Visual Studio Community 2017 - C++ Error How to fix the error "Windows SDK version 8.1" was not found? Visual Studio 2017 errors on standard headers How do I check if a Key is pressed on C++

Examples related to c

conflicting types for 'outchar' Can't compile C program on a Mac after upgrade to Mojave Program to find largest and second largest number in array Prime numbers between 1 to 100 in C Programming Language In c, in bool, true == 1 and false == 0? How I can print to stderr in C? Visual Studio Code includePath "error: assignment to expression with array type error" when I assign a struct field (C) Compiling an application for use in highly radioactive environments How can you print multiple variables inside a string using printf?

Examples related to makefile

MINGW64 "make build" error: "bash: make: command not found" "No rule to make target 'install'"... But Makefile exists How to overcome "'aclocal-1.15' is missing on your system" warning? How to install and use "make" in Windows? How to get a shell environment variable in a makefile? Using local makefile for CLion instead of CMake Difference between using Makefile and CMake to compile the code How to set child process' environment variable in Makefile Windows 7 - 'make' is not recognized as an internal or external command, operable program or batch file Debugging the error "gcc: error: x86_64-linux-gnu-gcc: No such file or directory"

Examples related to cmake

Copy file from source directory to binary directory using CMake CMake error at CMakeLists.txt:30 (project): No CMAKE_C_COMPILER could be found Installing cmake with home-brew CMake does not find Visual C++ compiler What's the CMake syntax to set and use variables? How do I add a library path in cmake? How to build x86 and/or x64 on Windows from command line with CMAKE? Difference between using Makefile and CMake to compile the code Add external libraries to CMakeList.txt c++ Cmake is not able to find Python-libraries