cmake-conan-setup

CMake toolchain for integration with Conan using cmake-conan, conan-setup.cmake.

NOTE:

• Since CMakeDeps and CMakeToolchain will be the only two cmake-related generators supported in Conan 2.X, this project won't consider the situation using any other cmake-related generators although the demonstration is using Conan 1.X.
• This project is INCOMPATIBLE with Conan 2.x for now since there are some bugs about conan_cmake_autodetect()...etc. Theoretically, this project should work with Conan 2.X after those bugs are fixed, which is the main goal of this project.

Motivation

This project aims to provide a NONINTRUSIVE way to integrate CMake with Conan using cmake-conan. It is because the typical usage of cmake-conan is intrusive, which uses APIs of cmake-conan inside the CMakeLists.txt directly. For example:

Click to expand

cmake_minimum_required(VERSION 3.9)
project(FormatOutput CXX)

list(APPEND CMAKE_MODULE_PATH ${CMAKE_BINARY_DIR})
list(APPEND CMAKE_PREFIX_PATH ${CMAKE_BINARY_DIR})

add_definitions("-std=c++11")

if(NOT EXISTS "${CMAKE_BINARY_DIR}/conan.cmake")
  message(STATUS "Downloading conan.cmake from https://github.com/conan-io/cmake-conan")
  file(DOWNLOAD "https://raw.githubusercontent.com/conan-io/cmake-conan/0.18.1/conan.cmake"
                "${CMAKE_BINARY_DIR}/conan.cmake"
                TLS_VERIFY ON)
endif()

include(${CMAKE_BINARY_DIR}/conan.cmake)

conan_cmake_configure(REQUIRES fmt/6.1.2
                      GENERATORS cmake_find_package)

conan_cmake_autodetect(settings)

conan_cmake_install(PATH_OR_REFERENCE .
                    BUILD missing
                    REMOTE conancenter
                    SETTINGS ${settings})

find_package(fmt)

add_executable(main main.cpp)
target_link_libraries(main fmt::fmt)

Moreover, there's an important problem that made Conan 2.X decide to deprecate cmake-conan, which is the Chicken-And-Egg(CAE) problem with CMakeToolchain (See more details on this issue). Therefore, this project provides an alternative way to use cmake-conan, which can solve the CAE problem.

Usage

Users just need to do the following two things:

• Prepare a conan recipe (conanfile.txt or conanfile.py) in the root source directory.
• Specify cache variable CMAKE_PROJECT_INCLUDE_BEFORE with conan-setup.cmake.

And then, all the installation of dependencies will be DONE automatically when they configure their projects.

You can grab a specific version of conan.cmake from cmake-conan to your project alongside with conan-setup.cmake. Otherwise, conan-setup.cmake will download the lastest version of conan.cmake from the master branch of cmake-conan.

Mechanism

The idea of this project is inspired by this article of Qt Blog, which introduces a custom toolchain file called auto-setup.cmake (You can check its content here). After simplifying the file and replacing the old APIs of cmake-conan with the new one into conan-setup.cmake, there are 4 steps of the mechanism:

1. Include conan.cmake and scan for conan recipes in the root source directory.
2. Create a new CMakeLists.txt, in which APIs of cmake-conan are used, by calling file(WRITE).
3. Configure the generated CMakeLists.txt by calling execute_process(COMMAND ${CMAKE_COMMAND}).
4. Include conan_toolchain.cmake generated by CMakeToolchain at the end of conan-setup.cmake.

Therefore, we can include conan_toolchain.cmake BEFORE the invocation of the first project() command. As we can see, the mechanism successfully solves the CAE problem.

Cache Variables

There are some default or custom variables that will take effect in conan-setup.cmake.

Cache Variables	Default Value (if not specified)	Effects
CMAKE_CONFIGURATION_TYPES	Debug;Release	If you're using Multi-Config generators, then it will run conan install command with all the config types listed in this variable recursively.
CMAKE_CONAN_OUPTUT_FOLDER	conan-deps	The subfolder where conan install command generates files inside the build directory.
CMAKE_CONAN_OUTPUT_QUIET	false	Disable the output message of running conan install command if we set it to true.
CMAKE_CONAN_ERROR_QUIET	false	Disable the error message of running conan install command if we set it to true.

Prerequisites

• CMake (at least version 3.23 for using some features needed in CMakePresets.json)
• Ninja (for using Ninja or Ninja Multi-Config generator)
• C/C++ Compilers

There are some installation guides for your reference:

• Installation Guide for Windows
• Installation Guide for Linux
• Installation Guide for MacOS

Configure Presets

There are some configure presets in CMakePresets.json. You can run cmake --list-presets command to check all the available configure presets for your platform, and then run cmake --preset <preset-name> to configure the project.

Windows-specific Presets

Click to expand

F:\GitRepo\cmake-conan-setup>cmake --list-presets
Available configure presets:

  "win32-msvc-x64-ninja-debug"      - Windows MSVC x64 (Ninja) Debug
  "win32-msvc-x64-ninja-release"    - Windows MSVC x64 (Ninja) Release
  "win32-msvc-x64-nmake-debug"      - Windows MSVC x64 (NMake Makefiles) Debug
  "win32-msvc-x64-nmake-release"    - Windows MSVC x64 (NMake Makefiles) Release
  "win32-msvc-x64-ninja-multi"      - Windows MSVC x64 (Ninja Multi-Config)
  "win32-msvc-x64-vs2019-multi"     - Windows MSVC x64 (Visual Studio 16 2019)
  "win32-msvc-x86-ninja-debug"      - Windows MSVC x86 (Ninja) Debug
  "win32-msvc-x86-ninja-release"    - Windows MSVC x86 (Ninja) Release
  "win32-msvc-x86-nmake-debug"      - Windows MSVC x86 (NMake Makefiles) Debug
  "win32-msvc-x86-nmake-release"    - Windows MSVC x86 (NMake Makefiles) Release
  "win32-msvc-x86-ninja-multi"      - Windows MSVC x86 (Ninja Multi-Config)
  "win32-msvc-x86-vs2019-multi"     - Windows MSVC x86 (Visual Studio 16 2019)
  "win32-gcc-x64-ninja-debug"       - Windows GCC x64 (Ninja) Debug
  "win32-gcc-x64-ninja-release"     - Windows GCC x64 (Ninja) Release
  "win32-gcc-x64-mingw-debug"       - Windows GCC x64 (MinGW Makefiles) Debug
  "win32-gcc-x64-mingw-release"     - Windows GCC x64 (MinGW Makefiles) Release
  "win32-gcc-x64-ninja-multi"       - Windows GCC x64 (Ninja Multi-Config)
  "win32-gcc-x86-ninja-debug"       - Windows GCC x86 (Ninja) Debug
  "win32-gcc-x86-ninja-release"     - Windows GCC x86 (Ninja) Release
  "win32-gcc-x86-mingw-debug"       - Windows GCC x86 (MinGW Makefiles) Debug
  "win32-gcc-x86-mingw-release"     - Windows GCC x86 (MinGW Makefiles) Release
  "win32-gcc-x86-ninja-multi"       - Windows GCC x86 (Ninja Multi-Config)
  "win32-clangcl-x64-ninja-debug"   - Windows ClangCL x64 (Ninja) Debug
  "win32-clangcl-x64-ninja-release" - Windows ClangCL x64 (Ninja) Release
  "win32-clangcl-x64-ninja-multi"   - Windows ClangCL x64 (Ninja Multi-Config)
  "win32-clangcl-x86-ninja-debug"   - Windows ClangCL x86 (Ninja) Debug
  "win32-clangcl-x86-ninja-release" - Windows ClangCL x86 (Ninja) Release
  "win32-clangcl-x86-ninja-multi"   - Windows ClangCL x86 (Ninja Multi-Config)
  "win32-clang-x64-ninja-debug"     - Windows Clang x64 (Ninja) Debug
  "win32-clang-x64-ninja-release"   - Windows Clang x64 (Ninja) Release
  "win32-clang-x64-ninja-multi"     - Windows Clang x64 (Ninja Multi-Config)
  "win32-clang-x86-ninja-debug"     - Windows Clang x86 (Ninja) Debug
  "win32-clang-x86-ninja-release"   - Windows Clang x86 (Ninja) Release
  "win32-clang-x86-ninja-multi"     - Windows Clang x86 (Ninja Multi-Config)

Linux-specific Presets

MacOS-specific Presets

Demonstrations

NOTE:

• You need to call vcvarsall.bat <argument> to setup environment before configuring the MSVC and ClangCL presets except those using Visaul Studio generator. (Only avaliable in cmd.exe not in powershell.exe)
• You may need to modify the "environment" settings yourself if the Clang/LLVM or GCC/MinGW Compiler is installed on other locations.

Integration with IDEs

Visual Studio Code (CMake Tools)

1. Open the project folder by Visual Studio Code.
2. Install CMake Tools extension.
3. Type "CMake: Select Configure Preset" on Command Palette (Ctrl+Shift+P).
4. Type "CMake: Configure" on Command Palette (Ctrl+Shift+P).