CMake: add target "ProgramOptionsHxx" so that users can link against the library when they've added it via add_subdirectory

Author: Fytch

CMakeLists.txt

@@ -1,56 +1,69 @@
-cmake_minimum_required( VERSION 3.1 )
-project( ProgramOptions )
+cmake_minimum_required( VERSION 3.5 )
+
+if( NOT DEFINED PROJECT_NAME )
+	set( PROGRAMOPTIONS_NOT_SUBPROJECT ON )
+endif()
+
+project( ProgramOptions LANGUAGES CXX VERSION 1.0.0 )
 set( CMAKE_CXX_STANDARD 11 )
 set( CMAKE_CXX_STANDARD_REQUIRED ON )
 set( CMAKE_CXX_EXTENSIONS OFF )
 
-option( PROGRAMOPTIONS_NO_EXCEPTIONS "disable exceptions" OFF )
-option( PROGRAMOPTIONS_NO_COLORS "disable colored output" OFF )
-option( PROGRAMOPTIONS_BUILD_TEST "build test" ON )
-option( PROGRAMOPTIONS_BUILD_EXAMPLES "build examples" ON )
-
-if( CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR
-	CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR
-	CMAKE_CXX_COMPILER_ID MATCHES "Intel" )
-	set( PROGRAMOPTIONS_GNU_OPTIONS TRUE )
-elseif( CMAKE_CXX_COMPILER_ID MATCHES "MSVC" )
-	set( PROGRAMOPTIONS_MS_OPTIONS TRUE )
-endif()
+add_library( ProgramOptionsHxx INTERFACE )
+target_include_directories( ProgramOptionsHxx INTERFACE "${CMAKE_CURRENT_LIST_DIR}/include" )
 
-include_directories( "${CMAKE_CURRENT_LIST_DIR}/include/" )
+if( PROGRAMOPTIONS_NOT_SUBPROJECT )
+	option( PROGRAMOPTIONS_NO_EXCEPTIONS "disable exceptions" OFF )
+	option( PROGRAMOPTIONS_NO_COLORS "disable colored output" OFF )
+	option( PROGRAMOPTIONS_BUILD_TEST "build test" ON )
+	option( PROGRAMOPTIONS_BUILD_EXAMPLES "build examples" ON )
 
-if( PROGRAMOPTIONS_GNU_OPTIONS )
-	set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wpedantic -Wno-deprecated -fno-rtti" )
-	set( CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -g -ggdb -fno-omit-frame-pointer" )
-	set( CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -march=native -DNDEBUG -s -flto" )
-endif()
+	if( CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR
+		CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR
+		CMAKE_CXX_COMPILER_ID MATCHES "Intel" )
+		set( PROGRAMOPTIONS_GNU_OPTIONS TRUE )
+	elseif( CMAKE_CXX_COMPILER_ID MATCHES "MSVC" )
+		set( PROGRAMOPTIONS_MS_OPTIONS TRUE )
+	endif()
 
-if( PROGRAMOPTIONS_NO_EXCEPTIONS )
-	add_definitions( -DPROGRAMOPTIONS_NO_EXCEPTIONS )
 	if( PROGRAMOPTIONS_GNU_OPTIONS )
-		set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-exceptions" )
-	elseif( PROGRAMOPTIONS_MS_OPTIONS )
-		set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /EHsc" )
+		set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wpedantic -Wno-deprecated -fno-rtti" )
+		set( CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -g -ggdb -fno-omit-frame-pointer" )
+		set( CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -march=native -DNDEBUG -s -flto" )
 	endif()
-endif()
 
-if( PROGRAMOPTIONS_NO_COLORS )
-	add_definitions( -DPROGRAMOPTIONS_NO_COLORS )
-endif()
+	if( PROGRAMOPTIONS_NO_EXCEPTIONS )
+		add_definitions( -DPROGRAMOPTIONS_NO_EXCEPTIONS )
+		if( PROGRAMOPTIONS_GNU_OPTIONS )
+			set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-exceptions" )
+		elseif( PROGRAMOPTIONS_MS_OPTIONS )
+			set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /EHsc" )
+		endif()
+	endif()
 
-if( PROGRAMOPTIONS_BUILD_TEST )
-	add_subdirectory( "${CMAKE_CURRENT_LIST_DIR}/ext/Catch2" )
+	if( PROGRAMOPTIONS_NO_COLORS )
+		add_definitions( -DPROGRAMOPTIONS_NO_COLORS )
+	endif()
 
-	file( GLOB_RECURSE test_src test/*.cxx )
-	add_executable( Test ${test_src} )
-	target_link_libraries( Test Catch2::Catch2 )
-endif()
+	if( PROGRAMOPTIONS_BUILD_TEST )
+		add_subdirectory( "${CMAKE_CURRENT_LIST_DIR}/ext/Catch2" )
 
-if( PROGRAMOPTIONS_BUILD_EXAMPLES )
-	file( GLOB_RECURSE examples_src examples/*.cxx )
-	foreach( src_name ${examples_src} )
-	    # CMake's regex engine doesn't support lazy evaluation (?), hence the hack below
-	    string( REGEX REPLACE "^.*[^a-zA-Z_]([a-zA-Z_]+)\\.cxx$" "\\1" exe_name ${src_name} )
-	    add_executable( ${exe_name} ${src_name} )
-	endforeach( src_name ${examples_src} )
+		file( GLOB_RECURSE test_src test/*.cxx )
+		add_executable( Test ${test_src} )
+		target_link_libraries( Test
+			Catch2::Catch2
+			ProgramOptionsHxx
+		)
+	endif()
+
+	if( PROGRAMOPTIONS_BUILD_EXAMPLES )
+		file( GLOB_RECURSE examples_src examples/*.cxx )
+		foreach( src_name ${examples_src} )
+		    # CMake's regex engine doesn't support lazy evaluation (?), hence the hack below
+		    string( REGEX REPLACE "^.*[^a-zA-Z_]([a-zA-Z_]+)\\.cxx$" "\\1" exe_name ${src_name} )
+		    add_executable( ${exe_name} ${src_name} )
+
+			target_link_libraries( ${exe_name} ProgramOptionsHxx )
+		endforeach( src_name ${examples_src} )
+	endif()
 endif()