1/** 2 * \file pcm/pcm_empty.c 3 * \ingroup PCM_Plugins 4 * \brief PCM Empty Plugin Interface 5 * \author Jaroslav Kysela <perex@perex.cz> 6 * \date 2006 7 */ 8/* 9 * PCM - Empty plugin 10 * Copyright (c) 2006 by Jaroslav Kysela <perex@perex.cz> 11 * 12 * 13 * This library is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU Lesser General Public License as 15 * published by the Free Software Foundation; either version 2.1 of 16 * the License, or (at your option) any later version. 17 * 18 * This program is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21 * GNU Lesser General Public License for more details. 22 * 23 * You should have received a copy of the GNU Lesser General Public 24 * License along with this library; if not, write to the Free Software 25 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 26 * 27 */ 28 29#include "pcm_local.h" 30#include "pcm_plugin.h" 31 32#ifndef PIC 33/* entry for static linking */ 34const char *_snd_module_pcm_empty = ""; 35#endif 36 37/*! \page pcm_plugins 38 39\section pcm_plugins_empty Plugin: Empty 40 41This plugin just redirects the PCM stream to another plugin. 42 43\code 44pcm.name { 45 type empty # Null PCM 46 slave STR # Slave name 47 # or 48 slave { # Slave definition 49 pcm STR # Slave PCM name 50 # or 51 pcm { } # Slave PCM definition 52 [format STR] # Slave format 53 [channels INT] # Slave channels 54 } 55} 56\endcode 57 58\subsection pcm_plugins_empty_funcref Function reference 59 60<UL> 61 <LI>_snd_pcm_empty_open() 62</UL> 63 64*/ 65 66/** 67 * \brief Creates a new Empty PCM 68 * \param pcmp Returns created PCM handle 69 * \param name Name of PCM 70 * \param root Root configuration node 71 * \param conf Configuration node with empty PCM description 72 * \param stream Stream type 73 * \param mode Stream mode 74 * \retval zero on success otherwise a negative error code 75 * \warning Using of this function might be dangerous in the sense 76 * of compatibility reasons. The prototype might be freely 77 * changed in future. 78 */ 79int _snd_pcm_empty_open(snd_pcm_t **pcmp, const char *name ATTRIBUTE_UNUSED, 80 snd_config_t *root, snd_config_t *conf, 81 snd_pcm_stream_t stream, int mode) 82{ 83 snd_config_t *slave = NULL, *sconf; 84 snd_config_iterator_t i, next; 85 int err; 86 87 snd_config_for_each(i, next, conf) { 88 snd_config_t *n = snd_config_iterator_entry(i); 89 const char *id; 90 if (snd_config_get_id(n, &id) < 0) 91 continue; 92 if (snd_pcm_conf_generic_id(id)) 93 continue; 94 if (strcmp(id, "slave") == 0) { 95 slave = n; 96 continue; 97 } 98 SNDERR("Unknown field %s", id); 99 return -EINVAL; 100 } 101 if (!slave) { 102 SNDERR("slave is not defined"); 103 return -EINVAL; 104 } 105 err = snd_pcm_slave_conf(root, slave, &sconf, 0); 106 if (err < 0) 107 return err; 108 err = snd_pcm_open_named_slave(pcmp, name, root, sconf, stream, 109 mode, conf); 110 snd_config_delete(sconf); 111 return err; 112} 113#ifndef DOC_HIDDEN 114SND_DLSYM_BUILD_VERSION(_snd_pcm_empty_open, SND_PCM_DLSYM_VERSION); 115#endif 116