[cmake-developers] why includes the Ninja decency contents sytemheader too?

[Claus Klein]

Yes, it should be configurable via one option flag.

The cmake user can control it but it is not well documented and different to configure depending on compiler and generator used:

#for ninja generator:
set(CMAKE_DEPFILE_FLAGS_CXX "-MMD -MT <OBJECT> -MF <DEPFILE>" CACHE STRING "dependency flag" FORCE)

# for makefile generator:
option(CMAKE_DEPENDS_IN_PROJECT_ONLY „do NOT use system header dependencies“ ON)

###############

But I am still wondering why different default behaviors in Nina and Makefile generators?

Claus

> Am 06.02.2018 um 13:22 schrieb Brad King <brad.king at kitware.com>:
> 
> Some people want system headers checked for $reasons, and others
> don't want them checked for $other_reasons.  The only way to satisfy
> both groups is to make it an option.
> 
> The internal `CMAKE_DEPFILE_FLAGS_${lang}` table of flags used for this
> would need to be extended with `CMAKE_DEPFILE_NOSYSTEM_FLAGS_${lang}`
> alternatives.  Some option would need to be introduced to choose.
> 
> -Brad