Conan not detecting "clean" installation of VS 2017

Hi everyone,

After setting up VS 2017 without the older SDKs or build tools and trying to execute conan v0.22.1 for the first time (with the devenv environment variables initialised of cource) I get this message (there is no problem if the VS 2015 build system or VS 2015 itself has been installed on the machine at the same time):

It seems to be the first time you've ran conan
Auto detecting your dev setup to initialize conan.conf
ERROR: Unable to find a working compiler
Default conan.conf settings
        os=Windows
        arch=x86_64
        build_type=Release
*** You can change them in ~/.conan/conan.conf ***
*** Or override with -s compiler='other' -s ...s***

CMake does detect my compiler as “Visual Studio 15 2017”.

Is there a workaround for this or a fix planned in an upcoming release?

[ghost]

While we’re on this subject, and to distribute knowledge that I acquired after much pain and suffering, I would suggest that you also open your Visual Studio 2017 Installer and make sure that the Windows 8.1 SDK is installed in addition to the Windows 10 SDK:

When building existing old VS projects, many times the referenced Windows SDK fails to be upgraded to v10 and just gets stuck at v8.1. This can happen even when upgrading from the interface of Visual Studio. Obviously, I have no idea why. For your own projects of course I guess you will make sure you are using the right SDK, setting it by hand, but when your scripts execute, downloading and automatically upgrading dependencies this will save you some time and brain cells murdered by extreme frustration.

[ghost]

To my understanding Visual Studio used to set the VSxxxCOMNTOOLS variable before, and conan (and other tools) could rely on it. For some reason that escapes me, VS has just stopped doing this in version 2017, so we need to either set an environment variable or execute this before running our builds:

set vs150comntools=C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\Tools\

If conan has already been executed on your system before this variable was set, it may be missing the highlighted lines below at the bottom, so you need to add them manually, like this if you want them the way conan would do it in previous VS versions by default:

[settings_defaults]

arch=x86_64 build_type=Release os=Windows compiler=Visual Studio compiler.version=15 compiler.runtime=MD

… or like this, also changing arch, if you want to be able to just run conan install, cmake and cmake build on the command line for your project without the cmake -G flag and the cmake build --config flag (I mention them here for example), which are needed not because of a conan issue but because of VS’s quirks.

[settings_defaults]

arch=x86 build_type=Debug os=Windows compiler=Visual Studio compiler.version=15 compiler.runtime=MDd <---- Attention MD becomes MDd

Of course, if you don’t mind being verbose, here’s an example of how you can skip all of that about conan.conf (still needing VS150COMNTOOLS though) and build a project while specifying everything on the command line:

mkdir build
cd build
conan install .. -s arch=x86_64 -s build_type=Debug -s os=Windows -s compiler="Visual Studio" -s compiler.version=15 -s compiler.runtime=MDd --build missing
cmake -G"Visual Studio 15 2017 Win64" ..
cmake --build . --config Debug