1 #ifndef PA_LINUX_ALSA_H 2 #define PA_LINUX_ALSA_H 3 4 /* 5 * $Id$ 6 * PortAudio Portable Real-Time Audio Library 7 * ALSA-specific extensions 8 * 9 * Copyright (c) 1999-2000 Ross Bencina and Phil Burk 10 * 11 * Permission is hereby granted, free of charge, to any person obtaining 12 * a copy of this software and associated documentation files 13 * (the "Software"), to deal in the Software without restriction, 14 * including without limitation the rights to use, copy, modify, merge, 15 * publish, distribute, sublicense, and/or sell copies of the Software, 16 * and to permit persons to whom the Software is furnished to do so, 17 * subject to the following conditions: 18 * 19 * The above copyright notice and this permission notice shall be 20 * included in all copies or substantial portions of the Software. 21 * 22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 23 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 24 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 25 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR 26 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 27 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 28 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 29 */ 30 31 /* 32 * The text above constitutes the entire PortAudio license; however, 33 * the PortAudio community also makes the following non-binding requests: 34 * 35 * Any person wishing to distribute modifications to the Software is 36 * requested to send the modifications to the original developer so that 37 * they can be incorporated into the canonical version. It is also 38 * requested that these non-binding requests be included along with the 39 * license above. 40 */ 41 42 /** @file 43 * @ingroup public_header 44 * @brief ALSA-specific PortAudio API extension header file. 45 */ 46 47 #include "portaudio.h" 48 49 #ifdef __cplusplus 50 extern "C" { 51 #endif 52 53 typedef struct PaAlsaStreamInfo 54 { 55 unsigned long size; 56 PaHostApiTypeId hostApiType; 57 unsigned long version; 58 59 const char *deviceString; 60 } 61 PaAlsaStreamInfo; 62 63 /** Initialize host API specific structure, call this before setting relevant attributes. */ 64 void PaAlsa_InitializeStreamInfo( PaAlsaStreamInfo *info ); 65 66 /** Instruct whether to enable real-time priority when starting the audio thread. 67 * 68 * If this is turned on by the stream is started, the audio callback thread will be created 69 * with the FIFO scheduling policy, which is suitable for realtime operation. 70 **/ 71 void PaAlsa_EnableRealtimeScheduling( PaStream *s, int enable ); 72 73 #if 0 74 void PaAlsa_EnableWatchdog( PaStream *s, int enable ); 75 #endif 76 77 /** Get the ALSA-lib card index of this stream's input device. */ 78 PaError PaAlsa_GetStreamInputCard( PaStream *s, int *card ); 79 80 /** Get the ALSA-lib card index of this stream's output device. */ 81 PaError PaAlsa_GetStreamOutputCard( PaStream *s, int *card ); 82 83 /** Set the number of periods (buffer fragments) to configure devices with. 84 * 85 * By default the number of periods is 4, this is the lowest number of periods that works well on 86 * the author's soundcard. 87 * @param numPeriods The number of periods. 88 */ 89 PaError PaAlsa_SetNumPeriods( int numPeriods ); 90 91 /** Set the maximum number of times to retry opening busy device (sleeping for a 92 * short interval inbetween). 93 */ 94 PaError PaAlsa_SetRetriesBusy( int retries ); 95 96 /** Set the path and name of ALSA library file if PortAudio is configured to load it dynamically (see 97 * PA_ALSA_DYNAMIC). This setting will overwrite the default name set by PA_ALSA_PATHNAME define. 98 * @param pathName Full path with filename. Only filename can be used, but dlopen() will lookup default 99 * searchable directories (/usr/lib;/usr/local/lib) then. 100 */ 101 void PaAlsa_SetLibraryPathName( const char *pathName ); 102 103 #ifdef __cplusplus 104 } 105 #endif 106 107 #endif 108