! Test optional character arguments.  We still need to pass a string! length for the absent argumentsprogram optional_string_1  implicit none  call test(1, "test");  call test(2, c=42, b="Hello World")containssubroutine test(i, a, b, c)  integer ::  i  character(len=4), optional :: a  character(len=*), optional :: b  integer, optional :: c  if (i .eq. 1) then    if (a .ne. "test") call abort  else    if (b .ne. "Hello World") call abort    if (c .ne. 42) call abort  end ifend subroutineend program