text: # - Try to find how to link to the standard math library, if anything at all is needed to do.
  # On most platforms this is automatic, but for example it's not automatic on QNX.
  #
  # Once done this will define
  #
  #  STANDARD_MATH_LIBRARY_FOUND - we found how to successfully link to the standard math library
  #  STANDARD_MATH_LIBRARY - the name of the standard library that one has to link to.
  #                            -- this will be left empty if it's automatic (most platforms).
  #                            -- this will be set to "m" on platforms where one must explicitly
  #                               pass the "-lm" linker flag.
  #
  # Copyright (c) 2010 Benoit Jacob <jacob.benoit.1@gmail.com>
  # Redistribution and use is allowed according to the terms of the 2-clause BSD license.
  
  
  include(CheckCXXSourceCompiles)
  
  # a little test program for c++ math functions.
  # notice the std:: is required on some platforms such as QNX
  
  set(find_standard_math_library_test_program
  "#include<cmath>
  int main() { std::sin(0.0); std::log(0.0f); }")
  
  # first try compiling/linking the test program without any linker flags
  
  set(CMAKE_REQUIRED_FLAGS "")
  set(CMAKE_REQUIRED_LIBRARIES "")
  CHECK_CXX_SOURCE_COMPILES(
    "${find_standard_math_library_test_program}"
    standard_math_library_linked_to_automatically
  )
  
  if(standard_math_library_linked_to_automatically)
  
    # the test program linked successfully without any linker flag.
    set(STANDARD_MATH_LIBRARY "")
    set(STANDARD_MATH_LIBRARY_FOUND TRUE)
  
  else()
  
    # the test program did not link successfully without any linker flag.
    # This is a very uncommon case that so far we only saw on QNX. The next try is the
    # standard name 'm' for the standard math library.
  
    set(CMAKE_REQUIRED_LIBRARIES "m")
    CHECK_CXX_SOURCE_COMPILES(
      "${find_standard_math_library_test_program}"
      standard_math_library_linked_to_as_m)
  
    if(standard_math_library_linked_to_as_m)
  
      # the test program linked successfully when linking to the 'm' library
      set(STANDARD_MATH_LIBRARY "m")
      set(STANDARD_MATH_LIBRARY_FOUND TRUE)
  
    else()
  
      # the test program still doesn't link successfully
      set(STANDARD_MATH_LIBRARY_FOUND FALSE)
  
    endif()
  
  endif()
  