CMake issues with target_include directories - c++

Question

I'm working on a new project, and trying to set up cmake from the ground up for the first time. I have two libraries that get built as targets in my project; libnet and liberror. I am linking libnet with liberror when I build the libnet target, and want to be able to #include header files that exist within liberror. I have the following added to the CMakeLists.txt for liberror:
target_include_directories(liberror SYSTEM PUBLIC core/error)
Now, I have the following added to the CMakeLists.txt for libnet:
target_link_libraries(libnet
PUBLIC
liberror)
So, liberror provides a header called ExceptionBuilder.hpp. When I try to do the following from libnet:
#include <core/error/ExceptionBuilder.hpp>
I get this error:
fatal error: core/error/ExceptionBuilder.hpp: No such file or directory
3 | #include <core/error/ExceptionBuilder.hpp>
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I am quite new to cmake, so probably just setting something up incorrectly here, but any ideas? Here is the project structure:
Project Structure
Here is the verbose build output:
nmcurtis#DESKTOP-JC26375:~/distro/build$ make
-- Boost version: 1.58.0
-- Configuring done
-- Generating done
-- Build files have been written to: /home/nmcurtis/distro/build
Consolidate compiler generated dependencies of target distro_core_error_objects
[ 11%] Built target distro_core_error_objects
Consolidate compiler generated dependencies of target distro_core_utility_objects
[ 16%] Built target distro_core_utility_objects
[ 22%] Linking CXX shared library libdistro_core_utility.so
/usr/local/gcc-11.3.0/bin/g++-11.3 -fPIC -fPIC -Wno-terminate -shared -Wl,-soname,libdistro_core_utility.so -o libdistro_core_utility.so CMakeFiles/distro_core_utility_objects.dir/Concepts.cpp.o
[ 22%] Built target distro_core_utility
[ 27%] Linking CXX shared library libdistro_core_error.so
/usr/local/gcc-11.3.0/bin/g++-11.3 -fPIC -fPIC -Wno-terminate -shared -Wl,-soname,libdistro_core_error.so -o libdistro_core_error.so CMakeFiles/distro_core_error_objects.dir/Exception.cpp.o CMakeFiles/distro_core_error_objects.dir/ExceptionBuilder.cpp.o -Wl,-rpath,/home/nmcurtis/distro/build/core/utility: ../utility/libdistro_core_utility.so
[ 27%] Built target distro_core_error
[ 33%] Linking CXX static library libdistro_core_utility_static.a
/usr/bin/ar qc libdistro_core_utility_static.a CMakeFiles/distro_core_utility_objects.dir/Concepts.cpp.o
/usr/bin/ranlib libdistro_core_utility_static.a
[ 33%] Built target distro_core_utility_static
[ 38%] Linking CXX static library libdistro_core_error_static.a
/usr/bin/ar qc libdistro_core_error_static.a CMakeFiles/distro_core_error_objects.dir/Exception.cpp.o CMakeFiles/distro_core_error_objects.dir/ExceptionBuilder.cpp.o
/usr/bin/ranlib libdistro_core_error_static.a
[ 38%] Built target distro_core_error_static
Consolidate compiler generated dependencies of target distro_core_net_objects
[ 44%] Building CXX object core/net/CMakeFiles/distro_core_net_objects.dir/Address.cpp.o
/home/nmcurtis/distro/core/net/Address.cpp:4:10: fatal error: core/error/ExceptionBuilder.hpp: No such file or directory
4 | #include <core/error/ExceptionBuilder.hpp>
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
core/net/CMakeFiles/distro_core_net_objects.dir/build.make:120: recipe for target 'core/net/CMakeFiles/distro_core_net_objects.dir/Address.cpp.o' failed
make[2]: *** [core/net/CMakeFiles/distro_core_net_objects.dir/Address.cpp.o] Error 1
CMakeFiles/Makefile2:262: recipe for target 'core/net/CMakeFiles/distro_core_net_objects.dir/all' failed
make[1]: *** [core/net/CMakeFiles/distro_core_net_objects.dir/all] Error 2
Makefile:135: recipe for target 'all' failed
make: *** [all] Error 2
nmcurtis#DESKTOP-JC26375:~/distro/build$

Answer 1

If you do target_include_directories(liberror SYSTEM PUBLIC core/error) you do not need core/error in #include <core/error/ExceptionBuilder.hpp>
Do this in core/error/CMakeLists.txt.
target_include_directories(liberror SYSTEM PUBLIC .)
# or
# target_include_directories(liberror SYSTEM PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
#include "ExceptionBuilder.hpp"
If you wish #include "core/error/ExceptionBuilder.hpp" then
do this in core/error/CMakeLists.txt.
target_include_directories(liberror SYSTEM PUBLIC ../..)
# or
# target_include_directories(liberror SYSTEM PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/../..)