anchor.diff:  program main
     use string, only : get_double, get_real, get_integer, str
  -  use iso_fortran_env, only : real32, real64, int32
  +  use iso_fortran_env, only : real32, real64, int32, output_unit, error_unit
     implicit none
   
     ! Enumerate the test-result array indices:
  
positive.code:   write(integer_string,*) integer_datum
  
    ! Test each string conversion function
    if ( get_double(real64_string)   == real64_datum         ) test_passed(get_double_) = .true.
    if ( get_real(real32_string)     == real32_datum         ) test_passed(get_real_) = .true.
    if ( get_integer(integer_string) == integer_datum        ) test_passed(get_integer_) = .true.
  
    ! Left-justify the expected results for comparison
    if ( adjustl(real64_string)      == str(real64_datum)  ) test_passed(str_d_) = .true.
  
negative.code: 
    ! Test each string conversion function
    if (all(test_passed)) then
       write(output_unit,*) "Test passed." 
    else
       if ( .not. test_passed(get_double_ )) write(error_unit,*) "Test get_double failed."
       if ( .not. test_passed(get_real_   )) write(error_unit,*) "Test get_real failed."
       if ( .not. test_passed(get_integer_)) write(error_unit,*) "Test get_integer failed."
       if ( .not. test_passed(str_d_      )) write(error_unit,*) "Test str_d failed."
       if ( .not. test_passed(str_r_      )) write(error_unit,*) "Test str_r failed."
       if ( .not. test_passed(str_i_      )) write(error_unit,*) "Test str_i failed."
    end if
  
  end program
  