CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

# ---- Project ----

# Note: update this to your new project's name and version
project(non_lin_optim 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 dependencies via CPM ----
# see https://github.com/TheLartians/CPM.cmake for more info

include(cmake/CPM.cmake)

# PackageProject.cmake will be used to make our target installable
CPMAddPackage("gh:TheLartians/PackageProject.cmake@1.8.0")

CPMAddPackage(
  NAME Eigen
  VERSION 3.4.0
  URL https://gitlab.com/libeigen/eigen/-/archive/3.4.0/eigen-3.4.0.tar.gz
  # Eigen's CMakelists are not intended for library use
  DOWNLOAD_ONLY YES 
)
add_library(Eigen INTERFACE IMPORTED)
target_include_directories(Eigen INTERFACE ${Eigen_SOURCE_DIR})

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

# Note: globbing sources is considered bad practice as CMake's generators may not detect new files
# automatically. Keep that in mind when changing files, or explicitly mention them here.
file(GLOB_RECURSE headers CONFIGURE_DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/include/*.h")
file(GLOB_RECURSE sources CONFIGURE_DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/src/*.cpp")

# ---- Create library ----

# Note: for header-only libraries change all PUBLIC flags to INTERFACE and create an interface
# target: add_library(${PROJECT_NAME} INTERFACE)
# add_library(${PROJECT_NAME} ${headers})
add_library(${PROJECT_NAME} INTERFACE)

set_target_properties(${PROJECT_NAME} PROPERTIES CXX_STANDARD 20)

# being a cross-platform target, we enforce standards conformance on MSVC
target_compile_options(${PROJECT_NAME} INTERFACE "$<$<COMPILE_LANG_AND_ID:CXX,MSVC>:/permissive->")

# Link dependencies
target_link_libraries(${PROJECT_NAME} INTERFACE Eigen)

target_include_directories(
  ${PROJECT_NAME} INTERFACE $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
                         $<INSTALL_INTERFACE:include/${PROJECT_NAME}-${PROJECT_VERSION}>
)

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

# the location where the project's version header will be placed should match the project's regular
# header paths
string(TOLOWER ${PROJECT_NAME}/version.h VERSION_HEADER_LOCATION)

packageProject(
  NAME ${PROJECT_NAME}
  VERSION ${PROJECT_VERSION}
  NAMESPACE ${PROJECT_NAME}
  BINARY_DIR ${PROJECT_BINARY_DIR}
  INCLUDE_DIR ${PROJECT_SOURCE_DIR}/include
  INCLUDE_DESTINATION include/${PROJECT_NAME}-${PROJECT_VERSION}
  VERSION_HEADER "${VERSION_HEADER_LOCATION}"
  COMPATIBILITY SameMajorVersion
  #DEPENDENCIES "fmt 7.1.3"
)