Re: poll(): IN/OUT vs {RD,WR}NORM

Mouse wrote:

> In sys/sys/poll.h, I see (in 1.4T, -current according to cvsweb, and
> everything I've checked in between):
>
> #define POLLIN          0x0001
> #define POLLPRI         0x0002
> #define POLLOUT         0x0004
> #define POLLRDNORM      0x0040
> #define POLLWRNORM      POLLOUT
> #define POLLRDBAND      0x0080
> #define POLLWRBAND      0x0100
>
> I can understand treating POLLWRNORM as identical to POLLOUT.  But why
> the distinction between POLLRDNORM and POLLIN?  Might anyone know the
> reason and be willing to explain?

I'd hazard a guess that you'll likely not get an explanation.

> ...  I'd still be curious where it came from.

Those answers are CVS:

  thoreau 55002> cvs annotate -r1.1 sys/sys/poll.h | grep define.POLL
  Annotations for sys/sys/poll.h
  ***************
  1.1          (mycroft  07-Sep-96): #define        POLLIN          0x0001
  1.1          (mycroft  07-Sep-96): #define        POLLPRI         0x0002
  1.1          (mycroft  07-Sep-96): #define        POLLOUT         0x0004
  1.1          (mycroft  07-Sep-96): #define        POLLRDNORM      0x0040
  1.1          (mycroft  07-Sep-96): #define        POLLWRNORM      POLLOUT
  1.1          (mycroft  07-Sep-96): #define        POLLRDBAND      0x0080
  1.1          (mycroft  07-Sep-96): #define        POLLWRBAND      0x0100
  1.1          (mycroft  07-Sep-96): #define        POLLERR         0x0008
  1.1          (mycroft  07-Sep-96): #define        POLLHUP         0x0010
  1.1          (mycroft  07-Sep-96): #define        POLLNVAL        0x0020
  thoreau 55003> cvs log -N -r1.1 sys/sys/poll.h
  ...
  ----------------------------
  revision 1.1
  date: 1996-09-08 03:42:49 +1000;  author: mycroft;  state: Exp;
  Definitions for poll(2).  Prototype it here.
  =============================================================================

Cheers,
Simon.