# try\_compile and genex in CMAKE\_MSVC\_RUNTIME\_LIBRARY

**URL:** <https://discourse.cmake.org/t/try-compile-and-genex-in-cmake-msvc-runtime-library/11757>\
**Category:** Code\
**Tags:** os:windows, gen:ninja\
**Created:** [September 23, 2024, 10:24pm UTC](https://discourse.cmake.org/t/try-compile-and-genex-in-cmake-msvc-runtime-library/11757 "2024-09-23T22:24:26Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![t-b](https://discourse.cmake.org/user_avatar/discourse.cmake.org/t-b/32/4957_2.png) [@t-b](https://discourse.cmake.org/u/t-b)\
**Post date:** [September 23, 2024, 10:24pm UTC](https://discourse.cmake.org/t/try-compile-and-genex-in-cmake-msvc-runtime-library/11757/1 "2024-09-23T22:24:26Z")

</div>

On Windows 11, ninja 1.11.1 and cmake 3.30.3 with VS 2022.

When I configure the following CMakeLists.txt

```cmake
cmake_minimum_required(VERSION 3.18...3.30 FATAL_ERROR)

set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")

project(cppTango LANGUAGES CXX)

try_compile(SOME_FLAG
            SOURCE_FROM_CONTENT main.cpp "int main(int, char**){}"
            OUTPUT_VARIABLE OUT)

message(STATUS "${OUT}")

```

with

```auto
cmake -G Ninja -B build -S . -DCMAKE_BUILD_TYPE=Release

```

I get

```auto
-- Change Dir: 'E:/projekte/cppTango/build/CMakeFiles/CMakeScratch/TryCompile-3luz9k'

Run Build Command(s): E:/projekte/common-orga-and-tools/tools/windows/ninja.exe -v cmTC_4ae17
[1/2] "C:\PROGRA~1\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.41.34120\bin\Hostx64\x64\cl.exe" /nologo /TP /DWIN32 /D_WINDOWS /EHsc /Ob0 /Od /RTC1 -MTd -Zi /showIncludes /FoCMakeFiles\cmTC_4ae17.dir\main.cpp.obj /FdCMakeFiles\cmTC_4ae17.dir\ /FS -c E:\projekte\cppTango\build\CMakeFiles\CMakeScratch\TryCompile-3luz9k\main.cpp
[2/2] C:\Windows\system32\cmd.exe /C "cd . && "C:\Program Files\CMake\bin\cmake.exe" -E vs_link_exe --intdir=CMakeFiles\cmTC_4ae17.dir --rc="C:\PROGRA~2\Windows Kits\10\bin\10.0.26100.0\x64\rc.exe" --mt="C:\PROGRA~2\Windows Kits\10\bin\10.0.26100.0\x64\mt.exe" --manifests -- "C:\PROGRA~1\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.41.34120\bin\Hostx64\x64\link.exe" /nologo CMakeFiles\cmTC_4ae17.dir\main.cpp.obj /out:cmTC_4ae17.exe /implib:cmTC_4ae17.lib /pdb:cmTC_4ae17.pdb /version:0.0 /machine:x64 /debug /INCREMENTAL /subsystem:console kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib && cd ."

-- Configuring done (0.4s)
-- Generating done (0.0s)
-- Build files have been written to: E:/projekte/cppTango/build

```

Note the `-MTd` where I would expect a `-MT`.

It does work if I use

```auto
set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded")

```

without generator expressions. Is that working as intended? I would expect that generator expressions in CMAKE\_MSVC\_RUNTIME\_LIBRARY are working.

---

<div class="post-metadata">

**Author:** ![Angew](https://discourse.cmake.org/user_avatar/discourse.cmake.org/angew/32/229_2.png) [@Angew](https://discourse.cmake.org/u/Angew)\
**Post date:** [September 24, 2024, 8:51am UTC](https://discourse.cmake.org/t/try-compile-and-genex-in-cmake-msvc-runtime-library/11757/2 "2024-09-24T08:51:09Z")

</div>

Does it help if you pass `CMAKE_BUILD_TYPE` down into the try-compile?

```auto
try_compile(SOME_FLAG
            SOURCE_FROM_CONTENT main.cpp "int main(int, char**){}"
            CMAKE_FLAGS -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE} #<=== added
            OUTPUT_VARIABLE OUT)

```

---

<div class="post-metadata">

**Author:** ![t-b](https://discourse.cmake.org/user_avatar/discourse.cmake.org/t-b/32/4957_2.png) [@t-b](https://discourse.cmake.org/u/t-b)\
**Post date:** [September 24, 2024, 9:00am UTC](https://discourse.cmake.org/t/try-compile-and-genex-in-cmake-msvc-runtime-library/11757/3 "2024-09-24T09:00:35Z")

</div>

Thanks for the reply, yes that fixes the issue. I’ll see how large the fallout is on other platforms.

---

<div class="post-metadata">

**Author:** ![t-b](https://discourse.cmake.org/user_avatar/discourse.cmake.org/t-b/32/4957_2.png) [@t-b](https://discourse.cmake.org/u/t-b)\
**Post date:** [September 25, 2024, 11:08am UTC](https://discourse.cmake.org/t/try-compile-and-genex-in-cmake-msvc-runtime-library/11757/4 "2024-09-25T11:08:18Z")

</div>

Reread the documentation again [1](https://cmake.org/cmake/help/latest/command/try_compile.html#other-behavior-settings) and found [CMAKE\_TRY\_COMPILE\_CONFIGURATION](https://cmake.org/cmake/help/latest/variable/CMAKE_TRY_COMPILE_CONFIGURATION.html) which solves it as well. And seems to be the official way.

---

<div class="post-metadata">

**Author:** ![Angew](https://discourse.cmake.org/user_avatar/discourse.cmake.org/angew/32/229_2.png) [@Angew](https://discourse.cmake.org/u/Angew)\
**Post date:** [September 25, 2024, 12:32pm UTC](https://discourse.cmake.org/t/try-compile-and-genex-in-cmake-msvc-runtime-library/11757/5 "2024-09-25T12:32:57Z")

</div>

> [@t-b](#):
>
> [CMAKE\_TRY\_COMPILE\_CONFIGURATION](https://cmake.org/cmake/help/latest/variable/CMAKE_TRY_COMPILE_CONFIGURATION.html) which solves it as well. And seems to be the official way.

Yes, that seems preferrable indeed, as it will also work with multi-config generators. I learned something new, thanks.

You might want to move the Solution marker to your post about this, so that people are not misled by what turns out to be an insufficient workaround.