Function cupsSideChannelRead

cups/sidechannel.c:94–268

 */

int					/* O - 0 on success, -1 on error */
cupsSideChannelRead(
    cups_sc_command_t *command,		/* O - Command code */
    cups_sc_status_t  *status,		/* O - Status code */
    char              *data,		/* O - Data buffer pointer */
    int               *datalen,		/* IO - Size of data buffer on entry, number of bytes in buffer on return */
    double            timeout)		/* I  - Timeout in seconds */
{
  char		*buffer;		/* Message buffer */
  ssize_t	bytes;			/* Bytes read */
  int		templen;		/* Data length from message */
  int		nfds;			/* Number of file descriptors */
#ifdef HAVE_POLL
  struct pollfd	pfd;			/* Poll structure for poll() */
#else /* select() */
  fd_set	input_set;		/* Input set for select() */
  struct timeval stimeout;		/* Timeout value for select() */
#endif /* HAVE_POLL */


  DEBUG_printf(("cupsSideChannelRead(command=%p, status=%p, data=%p, "
                "datalen=%p(%d), timeout=%.3f)", command, status, data,
		datalen, datalen ? *datalen : -1, timeout));

 /*
  * Range check input...
  */

  if (!command || !status)
    return (-1);

 /*
  * See if we have pending data on the side-channel socket...
  */

#ifdef HAVE_POLL
  pfd.fd     = CUPS_SC_FD;
  pfd.events = POLLIN;

  while ((nfds = poll(&pfd, 1,
		      timeout < 0.0 ? -1 : (int)(timeout * 1000))) < 0 &&
	 (errno == EINTR || errno == EAGAIN))
    ;

#else /* select() */
  FD_ZERO(&input_set);
  FD_SET(CUPS_SC_FD, &input_set);

  stimeout.tv_sec  = (int)timeout;
  stimeout.tv_usec = (int)(timeout * 1000000) % 1000000;

  while ((nfds = select(CUPS_SC_FD + 1, &input_set, NULL, NULL,
			timeout < 0.0 ? NULL : &stimeout)) < 0 &&
	 (errno == EINTR || errno == EAGAIN))
    ;

#endif /* HAVE_POLL */