40.1. "sunaudiodev" --- Access to Sun audio hardware
****************************************************

버전 2.6 폐지: The "sunaudiodev" module has been removed in Python 3.

This module allows you to access the Sun audio interface. The Sun
audio hardware is capable of recording and playing back audio data in
u-LAW format with a sample rate of 8K per second. A full description
can be found in the *audio(7I)* manual page.

The module "SUNAUDIODEV"  defines constants which may be used with
this module.

This module defines the following variables and functions:

exception sunaudiodev.error

   This exception is raised on all errors. The argument is a string
   describing what went wrong.

sunaudiodev.open(mode)

   This function opens the audio device and returns a Sun audio device
   object. This object can then be used to do I/O on. The *mode*
   parameter is one of "'r'" for record-only access, "'w'" for play-
   only access, "'rw'" for both and "'control'" for access to the
   control device. Since only one process is allowed to have the
   recorder or player open at the same time it is a good idea to open
   the device only for the activity needed. See *audio(7I)* for
   details.

   As per the manpage, this module first looks in the environment
   variable "AUDIODEV" for the base audio device filename.  If not
   found, it falls back to "/dev/audio".  The control device is
   calculated by appending "ctl" to the base audio device.


40.1.1. Audio Device Objects
============================

The audio device objects are returned by "open()" define the following
methods (except "control" objects which only provide "getinfo()",
"setinfo()", "fileno()", and "drain()"):

audio device.close()

   This method explicitly closes the device. It is useful in
   situations where deleting the object does not immediately close it
   since there are other references to it. A closed device should not
   be used again.

audio device.fileno()

   Returns the file descriptor associated with the device.  This can
   be used to set up "SIGPOLL" notification, as described below.

audio device.drain()

   This method waits until all pending output is processed and then
   returns. Calling this method is often not necessary: destroying the
   object will automatically close the audio device and this will do
   an implicit drain.

audio device.flush()

   This method discards all pending output. It can be used avoid the
   slow response to a user's stop request (due to buffering of up to
   one second of sound).

audio device.getinfo()

   This method retrieves status information like input and output
   volume, etc. and returns it in the form of an audio status object.
   This object has no methods but it contains a number of attributes
   describing the current device status. The names and meanings of the
   attributes are described in "<sun/audioio.h>" and in the
   *audio(7I)* manual page.  Member names are slightly different from
   their C counterparts: a status object is only a single structure.
   Members of the "play" substructure have "o_" prepended to their
   name and members of the "record" structure have "i_". So, the C
   member "play.sample_rate" is accessed as "o_sample_rate",
   "record.gain" as "i_gain" and "monitor_gain" plainly as
   "monitor_gain".

audio device.ibufcount()

   This method returns the number of samples that are buffered on the
   recording side, i.e. the program will not block on a "read()" call
   of so many samples.

audio device.obufcount()

   This method returns the number of samples buffered on the playback
   side. Unfortunately, this number cannot be used to determine a
   number of samples that can be written without blocking since the
   kernel output queue length seems to be variable.

audio device.read(size)

   This method reads *size* samples from the audio input and returns
   them as a Python string. The function blocks until enough data is
   available.

audio device.setinfo(status)

   This method sets the audio device status parameters. The *status*
   parameter is a device status object as returned by "getinfo()" and
   possibly modified by the program.

audio device.write(samples)

   Write is passed a Python string containing audio samples to be
   played. If there is enough buffer space free it will immediately
   return, otherwise it will block.

The audio device supports asynchronous notification of various events,
through the SIGPOLL signal.  Here's an example of how you might enable
this in Python:

   def handle_sigpoll(signum, frame):
       print 'I got a SIGPOLL update'

   import fcntl, signal, STROPTS

   signal.signal(signal.SIGPOLL, handle_sigpoll)
   fcntl.ioctl(audio_obj.fileno(), STROPTS.I_SETSIG, STROPTS.S_MSG)


40.2. "SUNAUDIODEV" --- Constants used with "sunaudiodev"
*********************************************************

버전 2.6 폐지: The "SUNAUDIODEV" module has been removed in Python 3.

This is a companion module to "sunaudiodev" which defines useful
symbolic constants like "MIN_GAIN", "MAX_GAIN", "SPEAKER", etc. The
names of the constants are the same names as used in the C include
file "<sun/audioio.h>", with the leading string "AUDIO_" stripped.
