This function is used to know if the library is compiled using integer 8 or 4 bytes long.
function use_8bytes_int() bind(c, name='__use_8bytes_int')
!! This function is used to know if the library is
!! compiled using integer 8 or 4 bytes long.
logical(kind=c_bool) :: use_8bytes_int
#ifdef USE_I8
use_8bytes_int = .true.
#else
use_8bytes_int = .false.
#endif
end function use_8bytes_int