CMakeLists.txt

cmake_minimum_required(VERSION 3.14 FATAL_ERROR)

# ---- Project ----

project(Greeter 
  VERSION 1.0
  LANGUAGES CXX
)

# ---- Include guards ----

if(${PROJECT_SOURCE_DIR} STREQUAL ${PROJECT_BINARY_DIR})
    message(FATAL_ERROR "In-source builds not allowed. Please make a new directory (called a build directory) and run CMake from there.")
endif()

# ---- Add source files ----

# Note: globbing sources is considered bad practice as CMake won't detect new files automatically.
# Remember to always invoke cmake after changing files, or explicitly mention them here.
FILE(GLOB_RECURSE headers "${CMAKE_CURRENT_SOURCE_DIR}/include/*.h")
FILE(GLOB_RECURSE sources "${CMAKE_CURRENT_SOURCE_DIR}/source/*.cpp")

# ---- Add dependencies via CPM (if required) ----
# see https://github.com/TheLartians/CPM.cmake for more info

# include(cmake/CPM.cmake)

# CPMAddPackage(
#   NAME cxxopts
#   GITHUB_REPOSITORY jarro2783/cxxopts
#   VERSION 2.2.0
#   OPTIONS
#     "CXXOPTS_BUILD_EXAMPLES Off"
#     "CXXOPTS_BUILD_TESTS Off"
# )

# ---- Create library ----

# Notes:
# for single header libraries use `add_library(Greeter INTERFACE)` instead 
# To create an executable use `add_executable(Greeter ${headers} ${sources})`
add_library(Greeter ${headers} ${sources})

# Note: for single header libraries use the following instead:
# set_target_properties(Greeter PROPERTIES INTERFACE_COMPILE_FEATURES cxx_std_17)
set_target_properties(Greeter PROPERTIES CXX_STANDARD 17)

# Link dependencies (if required)
# target_link_libraries(Greeter cxxopts)

# Node: change PUBLIC to INTERFACE for single header libraries  
target_include_directories(Greeter
  PUBLIC 
    $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
    $<INSTALL_INTERFACE:include/${PROJECT_NAME}-${PROJECT_VERSION}>
)

# ---- Create an installable target ----
# this allows users install and find the library via `find_package(Greeter)`.

include(cmake/packaging.cmake)