Using Visual Studio 2017 - CMake integration

Visual Studio 2017 comes with a CMake integration that allows to just open a folder that contains a CMakeLists.txt and Visual will use it to define the project build.

Conan can also be used in this setup to install dependencies. Let`s say that we are going to build an application, that depends on an existing conan package called Hello/0.1@user/testing. For the purpose of this example, you can quickly create this package typing in your terminal:

$ conan new Hello/0.1 -s
$ conan create . user/testing # Default conan profile is Release
$ conan create . user/testing -s build_type=Debug

The project we want to develop will be a simple application, with these 3 files in the same folder:

example.cpp

 #include <iostream>
 #include "hello.h"

 int main() {
     hello();
     std::cin.ignore();
 }

conanfile.txt

[requires]
Hello/0.1@user/testing

[generators]
cmake

CMakeLists.txt

project(Example CXX)
cmake_minimum_required(VERSION 2.8.12)

include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
conan_basic_setup()

add_executable(example example.cpp)
target_link_libraries(example ${CONAN_LIBS})

If we open Visual Studio 2017 (with CMake support installed), and in the Menu, select “Open Folder” and select the above folder, we will see something like the following error:

1> Command line: C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO\2017\COMMUNITY\COMMON7\IDE\COMMONEXTENSIONS\MICROSOFT\CMAKE\CMake\bin\cmake.exe  -G "Ninja" -DCMAKE_INSTALL_PREFIX:PATH="C:\Users\user\CMakeBuilds\df6639d2-3ef2-bc32-abb3-2cd1bdb3c1ab\install\x64-Debug"  -DCMAKE_CXX_COMPILER="C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.12.25827/bin/HostX64/x64/cl.exe"  -DCMAKE_C_COMPILER="C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.12.25827/bin/HostX64/x64/cl.exe"  -DCMAKE_BUILD_TYPE="Debug" -DCMAKE_MAKE_PROGRAM="C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO\2017\COMMUNITY\COMMON7\IDE\COMMONEXTENSIONS\MICROSOFT\CMAKE\Ninja\ninja.exe" "C:\Users\user\conanws\visual-cmake"
1> Working directory: C:\Users\user\CMakeBuilds\df6639d2-3ef2-bc32-abb3-2cd1bdb3c1ab\build\x64-Debug
1> -- The CXX compiler identification is MSVC 19.12.25831.0
1> -- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.12.25827/bin/HostX64/x64/cl.exe
1> -- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.12.25827/bin/HostX64/x64/cl.exe -- works
1> -- Detecting CXX compiler ABI info
1> -- Detecting CXX compiler ABI info - done
1> -- Detecting CXX compile features
1> -- Detecting CXX compile features - done
1> CMake Error at CMakeLists.txt:4 (include):
1>   include could not find load file:
1>
1>     C:/Users/user/CMakeBuilds/df6639d2-3ef2-bc32-abb3-2cd1bdb3c1ab/build/x64-Debug/conanbuildinfo.cmake

As expected, our CMakeLists.txt is using a include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake), and that file doesn’t exist yet, because conan has not installed the dependencies of this project yet. Visual Studio 2017 uses different build folders for each configuration. In this case, the default configuration at startup is x64-Debug. This means that we need to install the dependencies that match this configuration. Assuming that our default profile is using Visual Studio 2017 for x64 (it should typically be the default one created by conan if VS2017 is present), then all we need to specify is the -s build_type=Debug setting:

$ conan install . -s build_type=Debug -if=C:\Users\user\CMakeBuilds\df6639d2-3ef2-bc32-abb3-2cd1bdb3c1ab\build\x64-Debug

Now, you should be able to regenerate the CMake project from the IDE, Menu->CMake, build it, select the “example” executable to run, and run it.

Now, lets say that you want to build the Release application. You switch configuration from the IDE, and then the above error happens again. The dependencies for Release mode need to be installed too:

$ conan install . -if=C:\Users\user\CMakeBuilds\df6639d2-3ef2-bc32-abb3-2cd1bdb3c1ab\build\x64-Release

The process can be extended to x86 (passing -s arch=x86 in the command line), or to other configurations. For production usage, conan profiles are highly recommended.

Using cmake-conan

The cmake-conan project in https://github.com/conan-io/cmake-conan is a CMake script that runs an execute_process that automatically launches conan install to install dependencies. The settings passed in the command line will be deduced from the current CMake configuration, that will match the Visual Studio one. This script can be used to further automate the installation task:

project(Example CXX)
cmake_minimum_required(VERSION 2.8.12)

# Download automatically, you can also just copy the conan.cmake file
if(NOT EXISTS "${CMAKE_BINARY_DIR}/conan.cmake")
message(STATUS "Downloading conan.cmake from https://github.com/conan-io/cmake-conan")
    file(DOWNLOAD "https://raw.githubusercontent.com/conan-io/cmake-conan/v0.9/conan.cmake"
                "${CMAKE_BINARY_DIR}/conan.cmake")
endif()

include(${CMAKE_BINARY_DIR}/conan.cmake)

conan_cmake_run(CONANFILE conanfile.txt
                BASIC_SETUP)

add_executable(example example.cpp)
target_link_libraries(example ${CONAN_LIBS})

This code will manage to download the cmake-conan CMake script, and use it automatically, calling a conan install automatically.

There could be an issue, though, for the Release configuration. Internally, the Visual Studio 2017 defines the configurationType As RelWithDebInfo for Release builds. But conan default settings (in the conan settings.yml file), only have Debug and Release defined. It is possible to modify the settings.yml file, and add those extra build types. Then you should create the Hello package for those settings. And most existing packages, specially in central repositories, are built only for Debug and Release modes.

An easier approach is to change the CMake configuration in Visual: go to the Menu -> CMake -> Change CMake Configuration. That should open the CMakeSettings.json file, and there you can change the configurationType to Release:

{
  "name": "x64-Release",
  "generator": "Ninja",
  "configurationType": "Release",
  "inheritEnvironments": [ "msvc_x64_x64" ],
  "buildRoot": "${env.USERPROFILE}\\CMakeBuilds\\${workspaceHash}\\build\\${name}",
  "installRoot": "${env.USERPROFILE}\\CMakeBuilds\\${workspaceHash}\\install\\${name}",
  "cmakeCommandArgs": "",
  "buildCommandArgs": "-v",
  "ctestCommandArgs": ""
}

Note that the above CMake code is only valid for consuming existing packages. If you are also creating a package, you would need to make sure the right CMake code is executed, please check https://github.com/conan-io/cmake-conan/blob/master/README.md

Using tasks with tasks.vs.json

Another alternative is using file tasks feature of Visual Studio 2017. This way you can install dependencies by running conan install as task directly in the IDE.

All you need is to right click on your conanfile.py-> Configure Tasks (see the link above) and add the following to your tasks.vs.json.

Warning

The file tasks.vs.json is added to your local .vs folder so it is not supposed to be added to your version control system. There is also feature request to improve this process.

    {
      "tasks": [
        {
          "taskName": "conan install debug",
          "appliesTo": "conanfile.py",
          "type": "launch",
          "command": "${env.COMSPEC}",
          "args": [
            "conan install ${file} -s build_type=Debug -if C:/Users/user/CMakeBuilds/4c2d87b9-ec5a-9a30-a47a-32ccb6cca172/build/x64-Debug/"
          ]
        },
        {
          "taskName": "conan install release",
          "appliesTo": "conanfile.py",
          "type": "launch",
          "command": "${env.COMSPEC}",
          "args": [
            "conan install ${file} -s build_type=Release -if C:/Users/user/CMakeBuilds/4c2d87b9-ec5a-9a30-a47a-32ccb6cca172/build/x64-Release/"
          ]
        }
      ],
      "version": "0.2.1"
    }

Then just right click on your conanfile.py and launch your conan install and regenerate your CMakeLists.txt.