module sub_check
implicit none
contains
SUBROUTINE check ( ckind , fkind , vartype )
implicit none
INTEGER, INTENT(IN) :: ckind , fkind
CHARACTER (LEN=*) , INTENT(IN) :: vartype
IF ( ckind == fkind ) THEN
   WRITE(*,100) vartype
   100 format('  Default fortran & C variables of type '  , a ,  &
              'are interoperable  ' ) 
ELSE IF ( ckind < 0) THEN
   WRITE(*,200) vartype 
   200 format('A compatible fortran kind value is not available for type ',a) 
ELSE
   WRITE(*,300) vartype
   300 format(' default fortran & C variables of type ' , a , &
                        'are NOT interoperable '  )  
END IF
END SUBROUTINE check
end module sub_check

PROGRAM CandF
! Program to test cooperation between C and Fortran
USE, INTRINSIC :: iso_c_binding
use sub_check
implicit none
CALL check ( c_int , KIND( 1 ) , ' integer / int ' )
CALL check ( c_float , KIND( 1.0e0 ) , ' real / float ' )
CALL check ( c_double , KIND( 1.0d0 ) , 'double precision/double ' )
CALL check ( c_bool , KIND( .TRUE. ) , ' logical / boolean ' )
CALL check ( c_char , KIND( 'A' ) , ' character/ char ' )
CALL check ( c_float_complex , KIND( ( 1.0e0 , 1.0e0 ) ) , &
                        'complex/ float_complex ' )
END Program CandF