routine dir_mkfile (
    directory: file_t;
    flags: int;
    mode: mode_t;
    out newnode: mach_port_send_t);

Create a new file without linking it into the filesystem. You still must have write permission on the specified directory, even though it will not actually be written. Return in newnode a port to the file. flags are the same as for dir lookup, but O_CREAT and O_TRUNC are assumed even if not specified.