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MSVC compiler.version is not allowed to contain `.`

See original GitHub issue

We needed to keep track of subversions of MSVC, i.e. 16.8 vs 16.9. Why? because MSVC LTCG (LTO) is not compatible between minor versions. So if you compile a static library with LTCG in 16.8 you can’t link it to with 16.9.

We thought this was a easy solution - just change compiler.version to 16.8 instead of 16. But there are several assumptions in the conan codebase about the value of this setting, here is one: https://github.com/conan-io/conan/blob/develop/conans/client/tools/win.py#L429

For now I am adding compiler.minorversion but maybe this should be fixed.

Issue Analytics

State:
Created 2 years ago
Comments:5 (5 by maintainers)

Top GitHub Comments

1reaction

trucommented, Apr 28, 2021

No I was not aware of that - we are a bit behind on our conan versions. But that sounds good.

1reaction

trucommented, Apr 28, 2021

guessing this is the best source of the information: https://docs.microsoft.com/en-us/cpp/error-messages/compiler-errors-1/fatal-error-c1047?view=msvc-160

For example, you can't link a /LTCG library built by using Visual Studio 2019 version 16.7 to an app built by using Visual Studio 2019 version 16.8

But basically this is the same for GCC and Clang LTO as well. When using LTO/LTCG static libraries will contain the .o files that are NOT objects - they are just “bitcode” that is only supposed to be consumed by the same compiler that created it.