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/**
* \file pcm/pcm_empty.c
* \ingroup PCM_Plugins
* \brief PCM Null Plugin Interface
* \author Jaroslav Kysela <perex@perex.cz>
* \date 2006
*/
/*
* PCM - Null plugin
* Copyright (c) 2006 by Jaroslav Kysela <perex@perex.cz>
*
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "pcm_local.h"
#include "pcm_plugin.h"
#ifndef PIC
/* entry for static linking */
const char *_snd_module_pcm_empty = "";
#endif
/*! \page pcm_plugins
\section pcm_plugins_null Plugin: Null
This plugin discards contents of a PCM stream or creates a stream with zero
samples.
Note: This implementation uses devices /dev/null (playback, must be writable)
and /dev/full (capture, must be readable).
\code
pcm.name {
type null # Null PCM
}
\endcode
\subsection pcm_plugins_null_funcref Function reference
<UL>
<LI>_snd_pcm_empty_open()
</UL>
*/
/**
* \brief Creates a new Empty PCM
* \param pcmp Returns created PCM handle
* \param name Name of PCM
* \param root Root configuration node
* \param conf Configuration node with empty PCM description
* \param stream Stream type
* \param mode Stream mode
* \retval zero on success otherwise a negative error code
* \warning Using of this function might be dangerous in the sense
* of compatibility reasons. The prototype might be freely
* changed in future.
*/
int _snd_pcm_empty_open(snd_pcm_t **pcmp, const char *name ATTRIBUTE_UNUSED,
snd_config_t *root, snd_config_t *conf,
snd_pcm_stream_t stream, int mode)
{
snd_config_t *slave = NULL, *sconf;
snd_config_iterator_t i, next;
int err;
snd_config_for_each(i, next, conf) {
snd_config_t *n = snd_config_iterator_entry(i);
const char *id;
if (snd_config_get_id(n, &id) < 0)
continue;
if (snd_pcm_conf_generic_id(id))
continue;
if (strcmp(id, "slave") == 0) {
slave = n;
continue;
}
SNDERR("Unknown field %s", id);
return -EINVAL;
}
if (!slave) {
SNDERR("slave is not defined");
return -EINVAL;
}
err = snd_pcm_slave_conf(root, slave, &sconf, 0);
if (err < 0)
return err;
err = snd_pcm_open_named_slave(pcmp, name, root, sconf, stream,
mode, conf);
snd_config_delete(sconf);
return err;
}
#ifndef DOC_HIDDEN
SND_DLSYM_BUILD_VERSION(_snd_pcm_empty_open, SND_PCM_DLSYM_VERSION);
#endif
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