conan package for jolt has some difficulties

[cuppajoeman]

Recently we got jolt into conancenter which provides an easy way to install c++ dependencies.

I have confirmed that the library works well on linux, but now I am testing it on windows and there seems to be some issues.

Note: I have completely specified how to reproduce the issue in this issue

The gist of it that when you try and use joltphysics and run the hello world example then we get:

$ ./build/Release/jtest.exe
Version mismatch, make sure you compile the client code with the same Jolt version and compiler definitions!
Mismatching define JPH_FLOATING_POINT_EXCEPTIONS_ENABLED.

When I try and correct for this by adding the define we get:

$ ./build/Release/jtest.exe
Segmentation fault

I am not familiar with windows development and don't really have a good way of debugging this issue.

I was hoping that someone who is more savvy with windows development might be able to help debug this problem using whatever debugger they use to regularly debug programs on windows, to get started just install conan and then follow what I tried in the pull request, but then use the windows debugger to try and see what is going wrong. (MVSC is the used compiler in this situation)

If you can help then thanks a lot 👍

[jrouwe]

I don't really want to go through the trouble of installing conan and there's not much to go on in this ticket.

• Can you build a Debug build instead of a Release build (maybe an assert will fire)?
• Can you run jtest.exe from the MSVC IDE (just drag jtest.exe from explorer in MSVC and press F5) and report the callstack of this crash?

[cuppajoeman]

I made some progress, the segmentation fault seemed to be a red herring. After I removed my build directory and tried it over, I was able to get it to work correctly. So as long as the client code has this line in their CMakeLists.txt things should work:

add_definitions(-DJPH_FLOATING_POINT_EXCEPTIONS_ENABLED)

I wanted to ask if this was expected behavior based on my understanding of conan, from what I understand it builds the libraries before your project is built and stores the binaries in a directory on your computer. I suppose int his case the option FLOATING_POINT_EXCEPTIONS_ENABLED was enabled because by default this line exists:

JoltPhysics/Build/CMakeLists.txt

Line 40 in 25e920c

option(FLOATING_POINT_EXCEPTIONS_ENABLED "Enable floating point exceptions" ON)

and because we are on windows, then this if statement will go through and create the definition:

JoltPhysics/Jolt/Jolt.cmake

Lines 527 to 529 in 25e920c

	if (FLOATING_POINT_EXCEPTIONS_ENABLED AND "${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
	target_compile_definitions(Jolt PUBLIC "$<$<CONFIG:Debug,Release>:JPH_FLOATING_POINT_EXCEPTIONS_ENABLED>")
	endif()

So the prebuilt binary will have that definition in-place, so would it then be expected that when we build our client code that we must also have this definition in place or else things wouldn't work correctly?

And would this then imply that whenever we have a option set to true, which in-turn creates a define that was must also create this define in the client code to avoid mismatched defines? (in the context of using conan)

[jrouwe]

So the prebuilt binary will have that definition in-place, so would it then be expected that when we build our client code that we must also have this definition in place or else things wouldn't work correctly?

Yes, all defines that start with JPH_ must match between library and client code. Normally cmake takes care of this because of the PUBLIC in target_compile_definitions (this means: set the definition on Jolt and anything that uses it). Conan somehow interferes with this and prevents that from working. I'm not familiar with conan, so I can't give any suggestions as to why that may be happening.

And would this then imply that whenever we have a option set to true, which in-turn creates a define that was must also create this define in the client code to avoid mismatched defines? (in the context of using conan)

Yes. In this case you may opt to turn off FLOATING_POINT_EXCEPTIONS_ENABLED for the library, as its only purpose is to have extra run-time validation. The setting is off in Jolt's Distribution build, which is the configuration that's supposed to be used by shipping executables.