vtkCompilerExtras.cmake

if(CMAKE_COMPILER_IS_GNUCXX)

  include(CheckCXXCompilerFlag)

  # Addtional warnings for GCC
  set(CMAKE_CXX_FLAGS_WARN "-Wnon-virtual-dtor -Wno-long-long -ansi -Wcast-align -Wchar-subscripts -Wall -Wextra -Wpointer-arith -Wformat-security -Woverloaded-virtual -Wshadow -Wunused-parameter -fno-check-new -fno-common")

  # This flag is useful as not returning from a non-void function is an error
  # with MSVC, but it is not supported on all GCC compiler versions
  check_cxx_compiler_flag(-Werror=return-type HAVE_GCC_ERROR_RETURN_TYPE)
  if(HAVE_GCC_ERROR_RETURN_TYPE)
    set(CMAKE_CXX_FLAGS_ERROR "-Werror=return-type")
  endif()

  # If we are compiling on Linux then set some extra linker flags too
  if(CMAKE_SYSTEM_NAME MATCHES Linux)
    option(VTK_LINKER_FATAL_WARNINGS "Specify if linker warnings must be considered as errors." OFF)
    mark_as_advanced(VTK_LINKER_FATAL_WARNINGS)
    if(VTK_LINKER_FATAL_WARNINGS)
      set(VTK_EXTRA_SHARED_LINKER_FLAGS "-Wl,--fatal-warnings")
    endif()
    set(CMAKE_SHARED_LINKER_FLAGS
      "${VTK_EXTRA_SHARED_LINKER_FLAGS} -Wl,--no-undefined -lc ${CMAKE_SHARED_LINKER_FLAGS}")
    set(CMAKE_MODULE_LINKER_FLAGS
      "${VTK_EXTRA_SHARED_LINKER_FLAGS} -Wl,--no-undefined -lc ${CMAKE_SHARED_LINKER_FLAGS}")
    set (CMAKE_EXE_LINKER_FLAGS
      "${VTK_EXTRA_SHARED_LINKER_FLAGS} -Wl,--no-undefined -lc ${CMAKE_SHARED_LINKER_FLAGS}")
  endif()

  # Set up the debug CXX_FLAGS for extra warnings
  option(VTK_EXTRA_COMPILER_WARNINGS
    "Add compiler flags to do stricter checking when building debug." OFF)
  if(VTK_EXTRA_COMPILER_WARNINGS)
    set(CMAKE_CXX_FLAGS_RELWITHDEBINFO
      "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} ${CMAKE_CXX_FLAGS_WARN}")
    set(CMAKE_CXX_FLAGS_DEBUG
      "${CMAKE_CXX_FLAGS_DEBUG} ${CMAKE_CXX_FLAGS_WARN} ${CMAKE_CXX_FLAGS_ERROR}")
  endif()
endif()