Google Earth C ++ API Library Errors on Ubuntu - c++

Question

I'm new to this forum, but I've seen it a few times while trying to search for a solution to this problem. I'm trying to generate KML files to use in Google Earth using a C++ API library I found for Ubuntu (libkml-dev_1.2.0-1ubuntu6_amd64). I installed the package using the command sudo apt-get install libkml-dev, came back successful. Afterwards, I used the command line terminal to navigate to the examples folder to try and execute the program 'helloworld.cc' with the command g++ helloworld.cc -o helloworld, but then got a slew of errors (mainly claiming that kmldom is an undefined reference). Sorry, I wanted to attach the text file, but don't know how so I included a sample of the error below. I've searched high and low all week, made sure the header files were indeed included in the download, and even contacted the Google Earth developers about the problem (and they responded that they have nothing to do with this and to redirect all questions regarding this issue to StackOverflow).
Does anyone know what is causing this problem(s) and what I can do to resolve this so I can move on please?
/tmp/cc5u2JyV.o: In function HelloKml(bool)': helloworld.cc:(.text+0x17): undefined reference to kmldom::KmlFactory::GetFactory()'
helloworld.cc:(.text+0x27): undefined reference to kmldom::KmlFactory::CreateCoordinates() const' helloworld.cc:(.text+0x328): undefined reference to kmldom::AsPoint(boost::intrusive_ptrkmldom::Element)'
/tmp/cc5u2JyV.o: In function boost::intrusive_ptr<kmldom::Coordinates>::intrusive_ptr(kmldom::Coordinates*, bool)': helloworld.cc:(.text._ZN5boost13intrusive_ptrIN6kmldom11CoordinatesEEC2EPS2_b[_ZN5boost13intrusive_ptrIN6kmldom11CoordinatesEEC5EPS2_b]+0x3d): undefined reference to kmlbase::intrusive_ptr_add_ref(kmlbase::Referent*)'
/tmp/cc5u2JyV.o: In function boost::intrusive_ptr<kmldom::Coordinates>::~intrusive_ptr()': helloworld.cc:(.text._ZN5boost13intrusive_ptrIN6kmldom11CoordinatesEED2Ev[_ZN5boost13intrusive_ptrIN6kmldom11CoordinatesEED5Ev]+0x23): undefined reference to kmlbase::intrusive_ptr_release(kmlbase::Referent*)'
/tmp/cc5u2JyV.o: In function boost::intrusive_ptr<kmldom::Geometry>::intrusive_ptr(boost::intrusive_ptr<kmldom::Geometry> const&)': helloworld.cc:(.text._ZN5boost13intrusive_ptrIN6kmldom8GeometryEEC2ERKS3_[_ZN5boost13intrusive_ptrIN6kmldom8GeometryEEC5ERKS3_]+0x35): undefined reference to kmlbase::intrusive_ptr_add_ref(kmlbase::Referent*)'
collect2: ld returned 1 exit status

Answer 1

When you compile application that uses library, you need to link it when your application compiles. So, try using this parameters:
To specify a directory to search for your libs, use -L:
-L/data[...]/lib
To specify the actual library name, use -l:
-labc (links abc.a or abc.so)
To specify a directory to search for include files, use -I:
-I/data[...]/lib

Answer 2

I've found the solution. The problem is that you are linking libkml incrorrectly. You should find the paths to the header files and to the library files (*.so). I found them here:
/usr/include/kml/ (include dit with headers),
/usr/lib/x86_64-linux-gnu/ (library dir).
I use CMake and CMakeLists.txt for a project. Using libkml may look like this:
`cmake_minimum_required (VERSION 3.2)
# Set language standard
set(CMAKE_CXX_STANDARD "11")
project (test_proj)
add_definitions(-std=c++11)
# Set default build type to RelWithDebInfo if not specified
if (NOT CMAKE_BUILD_TYPE)
message (STATUS "Default CMAKE_BUILD_TYPE not set using Release with Debug Info")
set (CMAKE_BUILD_TYPE "RelWithDebInfo" CACHE
STRING "Choose the type of build, options are: None Debug Release RelWithDebInfo MinSizeRel"
FORCE)
endif()
# linking boost library
find_package(Boost COMPONENTS system filesystem thread REQUIRED)
if(NOT Boost_FOUND)
message(SEND_ERROR "Failed to find boost.")
return()
else()
include_directories(${Boost_INCLUDE_DIRS})
endif()
add_executable(test_proj main.cpp)
set (LibKML_INCLUDE_DIRS /usr/include/kml/)
set (LibKML_LIBRARIES /usr/lib/x86_64-linux-gnu/libkmlbase.so /usr/lib/x86_64-linux-gnu/libkmlconvenience.so /usr/lib/x86_64-linux-gnu/libkmldom.so /usr/lib/x86_64-linux-gnu/libkmlengine.so /usr/lib/x86_64-linux-gnu/libkmlregionator.so /usr/lib/x86_64-linux-gnu/libkmlxsd.so)
message("LibKML is at: ${LibKML_INCLUDE_DIRS} and ${LibKML_LIBRARIES}")
message("Boost is at: ${Boost_INCLUDE_DIRS} and ${Boost_LIBRARIES}")
target_include_directories(test_proj
PUBLIC
${LibKML_INCLUDE_DIRS}
${Boost_INCLUDE_DIRS} )
target_link_libraries(test_proj
PUBLIC
${LibKML_LIBRARIES} ${Boost_LIBRARIES})
install(TARGETS test_proj EXPORT test_proj_export)
export(EXPORT test_proj_export FILE cmake/test_proj-targets.cmake)`