ros2 foxy including header file from other package

edit

I have two packages, temp_lib and temp_pkg. In temp_lib I have a file temp.hpp that I would like to include in other packages, but when I attempt to do so by writing in #include "temp_lib/temp.hpp" in a cpp file in temp_pkg then it says this header cannot be found.

The problem is i'm not really sure how to set up the CMakeLists file for the library.

How can I set these packages up for this to be possible?

LIBRARY CMAKE

cmake_minimum_required(VERSION 3.5)
project(temp_lib)

# find dependencies
find_package(ament_cmake REQUIRED)
find_package(rclcpp REQUIRED)

install(TARGETS
  DESTINATION lib/${PROJECT_NAME}
  PUBLIC_HEADER DESTINATION include/${PROJECT_NAME}/
  )

install(DIRECTORY include/${PROJECT_NAME}/
  DESTINATION include/${PROJECT_NAME}
  FILES_MATCHING PATTERN "*.h"
  PATTERN ".git" EXCLUDE)

ament_package()

temp.hpp (from temp_lib)

#ifndef TEMP_LIB__TEMP_HPP_
#define TEMP_LIB__TEMP_HPP_

#include <iostream>

#endif // TEMP_LIB__TEMP_HPP_

PKG CMAKE

cmake_minimum_required(VERSION 3.5)
project(temp_pkg)

# find dependencies
find_package(ament_cmake REQUIRED)
find_package(rclcpp REQUIRED)
find_package(temp_lib REQUIRED)

include_directories(
  ${temp_lib_INCLUDE_DIRS}
)

add_executable(test src/temp.cpp)
ament_target_dependencies(test rclcpp temp_lib)

install(TARGETS
  test
  DESTINATION lib/${PROJECT_NAME}
)

ament_package()

temp.cpp (from temp_pkg)

#include "temp_lib/temp.hpp"
int main(int argc, char *argv[]) {
  std::cout << "it works" << std::endl;
  return 0;
}

Edit: for legibility I removed some repeated standard parts of the CMake files, these are

# Default to C99
if(NOT CMAKE_C_STANDARD)
  set(CMAKE_C_STANDARD 99)
endif()

# Default to C++14
if(NOT CMAKE_CXX_STANDARD)
  set(CMAKE_CXX_STANDARD 14)
endif()

if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
  add_compile_options(-Wall -Wextra -Wpedantic)
endif()

and

if(BUILD_TESTING)
  find_package(ament_lint_auto REQUIRED)
  # the following line skips the linter which checks for copyrights
  # uncomment the line when a copyright and license is not present in all source files
  #set(ament_cmake_copyright_FOUND TRUE)
  # the following line skips cpplint (only works in a git repo)
  # uncomment the line when this package is not in a git repo
  #set(ament_cmake_cpplint_FOUND TRUE)
  ament_lint_auto_find_test_dependencies()
endif()