Add Boost CMake module

[shrijitsingh99]

Referenced in #2559.
Removed the replicated supported versions & cleaned up the modules section.
@SergioRAgostinho Is this what you had in mind?

[SergioRAgostinho]

You got the general idea but your solution still needs work. With the current approach you're breaking pcl's the config file. Downstream projects, like the tutorials job, are not configuring properly.

Have a look at what was done in #1421.

pcl_find_boost.cmake, needs to be migrated into it's own FindBoost.cmake module inside pcl/cmake/Modules. That way it can be invoked in both stages: when compiling pcl and when configuring a downstream project.

[shrijitsingh99]

You got the general idea but your solution still needs work. With the current approach you're breaking pcl's the config file. Downstream projects, like the tutorials job, are not configuring properly.

Have a look at what was done in #1421.

pcl_find_boost.cmake, needs to be migrated into it's own FindBoost.cmake module inside pcl/cmake/Modules. That way it can be invoked in both stages: when compiling pcl and when configuring a downstream project.

Got what you are trying to say, was initially thinking of doing something like suggested but wasn't sure then. Will incorporate the changes suggested in the next commit.

[shrijitsingh99]

What's the idea behind setting separate variables like BOOST_INCLUDE_DIRS when Boost_INCLUDE_DIRS is already set?

[taketwo]

Consider these lines:

pcl/PCLConfig.cmake.in

Lines 321 to 325 in 2133857

	string(TOUPPER "${_component}" COMPONENT)
	string(TOUPPER "${_lib}" LIB)
	string(REGEX REPLACE "[.-]" "_" LIB ${LIB})
	if(${LIB}_FOUND)
	list(APPEND PCL_${COMPONENT}_INCLUDE_DIRS ${${LIB}_INCLUDE_DIRS})

We try to treat all external dependencies uniformly, thus the convention is that finder scripts set variables prefixed with capitalized name of the dependency. If it wasn't the case, we'd need to keep track of which library is called Library, which library, and which LIBRARY.

[shrijitsingh99]

pcl_find_boost.cmake, needs to be migrated into it's own FindBoost.cmake module inside pcl/cmake/Modules. That way it can be invoked in both stages: when compiling pcl and when configuring a downstream project.

Made the appropriate changes.

I thought of using pkg-config initially, but it seems Boost doesn't have support for it currently.

[kunaltyagi]

Would this stop overriding the Boost_LIBRARIES variable for anyone consuming PCL? There's an issue open (and verified) which says that find_package(Boost) before find_package(PCL) causes PCL to override the Boost libraries

[kunaltyagi]

Also, what's the relationship of pcl_find_boost.cmake with Modules/FindBoost.cmake (because I notice it's untouched in this PR)

[shrijitsingh99]

Also, what's the relationship of pcl_find_boost.cmake with Modules/FindBoost.cmake (because I notice it's untouched in this PR)

That is to be removed.

Would this stop overriding the Boost_LIBRARIES variable for anyone consuming PCL? There's an issue open (and verified) which says that find_package(Boost) before find_package(PCL) causes PCL to override the Boost libraries

Currently, no. It should be possible though to append the already existing found components to the list of found components.

[stale]

Marking this as stale due to 30 days of inactivity. Commenting or adding a new commit to the pull request will revert this.