External Include on MSVC

Code
1

Hi,

I found that cmake seems to support -external:I since https://gitlab.kitware.com/cmake/cmake/-/merge_requests/4766.

I have something something like this in my project:

get_property(date_include_dirs TARGET date PROPERTY INTERFACE_INCLUDE_DIRECTORIES)
set_property(TARGET date PROPERTY INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "${date_include_dirs}")

To make third party libs via fetch Content System Includes.

On MSVC this still leads to:

/I"C:\Users\LeonD\Documents\beans\build-v
         s16\_deps\date-src\include"

while on CLang / GCC it correctly leads to:

-isystem /home/leon/Projects/beans/build/_deps/date-src/include

Why is it not using -external:I on MSVC? Isn’t this what above mentioned Merge Request did implement or do I miss something?

2

Are you using a new enough MSVC compiler? It is only enabled for a toolchain that was released a few months ago.

3

Additionally, it is only supported with the Makefiles and Ninja generator as Visual Studio generation seems quite a bit more involved and I didn’t have the time to do that as well.

4

Oh yes it’s with the Visual Studio Generator. Is there any workaround?

5

No, the XML elements that are needed in the .vcxproj need to be generated at the right place and that code has not yet been written.