Re: NULL struct to futimes does not return current date/time on GNU/Hurd

[Thomas Schwinge]

Hey Roland!  Aren't you supposed to cure your wrist?

On Tue, Oct 10, 2006 at 02:29:12AM -0700, Roland McGrath wrote:
> Thanks for the clarification.  I committed a libc change that should work.

Confirmed that it works.


But may I ask why you didn't like the function to be the way Samuel and I
proposed:

#v+
int
__futimes (int fd, const struct timeval tvp[2])
{
  error_t err;
  time_value_t new_atime, new_mtime;

  if (tvp == NULL)
      /* Setting the number of microseconds to `-1' tells the
         underlying filesystems to use the current time.  */
    new_atime.microseconds = new_mtime.microseconds = -1;
  else
    {
      new_atime.seconds = tvp[0].tv_sec;
      new_atime.microseconds = tvp[0].tv_usec;
      new_mtime.seconds = tvp[1].tv_sec;
      new_mtime.microseconds = tvp[1].tv_usec;
    }

  err = HURD_DPORT_USE (fd, __file_utimes (port, new_atime, new_mtime));
  return err ? __hurd_dfail (fd, err) : 0;
}
#v-

Compared to yours:

#v+
int
__futimes (int fd, const struct timeval tvp[2])
{
  union tv
  {
    struct timeval tv;
    time_value_t tvt;
  };
  const union tv *u = (const union tv *) tvp;
  union tv nulltv[2];
  error_t err;

  if (tvp == NULL)
    {
      /* Setting the number of microseconds to `-1' tells the
         underlying filesystems to use the current time.  */
      nulltv[0].tvt.microseconds = nulltv[1].tvt.microseconds = -1;
      u = nulltv;
    }

  err = HURD_DPORT_USE (fd, __file_utimes (port, u[0].tvt, u[1].tvt));
  return err ? __hurd_dfail (fd, err) : 0;
#v-

... ours needs to copy the four values for `tvp != NULL', but avoids the
union and the cast you need in yours.


And by the way: why do we need both `struct timeval' and `struct
time_value'?  Given that we nevertheless assume them to be equal in the
code, isn't there a way to get rid of Mach's `struct time_value'?


Regards,
 Thomas

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