1 #ifndef PA_LINUX_ALSA_H
2 #define PA_LINUX_ALSA_H
5 * $Id: pa_linux_alsa.h 1597 2011-02-11 00:15:51Z dmitrykos $
6 * PortAudio Portable Real-Time Audio Library
7 * ALSA-specific extensions
9 * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
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:
19 * The above copyright notice and this permission notice shall be
20 * included in all copies or substantial portions of the Software.
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
23 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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32 * The text above constitutes the entire PortAudio license; however,
33 * the PortAudio community also makes the following non-binding requests:
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
43 * @ingroup public_header
44 * @brief ALSA-specific PortAudio API extension header file.
47 #include "portaudio.h"
53 typedef struct PaAlsaStreamInfo
56 PaHostApiTypeId hostApiType;
57 unsigned long version;
59 const char *deviceString;
63 /** Initialize host API specific structure, call this before setting relevant attributes. */
64 void PaAlsa_InitializeStreamInfo( PaAlsaStreamInfo *info );
66 /** Instruct whether to enable real-time priority when starting the audio thread.
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.
71 void PaAlsa_EnableRealtimeScheduling( PaStream *s, int enable );
74 void PaAlsa_EnableWatchdog( PaStream *s, int enable );
77 /** Get the ALSA-lib card index of this stream's input device. */
78 PaError PaAlsa_GetStreamInputCard( PaStream *s, int *card );
80 /** Get the ALSA-lib card index of this stream's output device. */
81 PaError PaAlsa_GetStreamOutputCard( PaStream *s, int *card );
83 /** Set the number of periods (buffer fragments) to configure devices with.
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.
89 PaError PaAlsa_SetNumPeriods( int numPeriods );
91 /** Set the maximum number of times to retry opening busy device (sleeping for a
92 * short interval inbetween).
94 PaError PaAlsa_SetRetriesBusy( int retries );
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.
101 void PaAlsa_SetLibraryPathName( const char *pathName );