portaudio.h   portaudio.h 
#ifndef PORTAUDIO_H #ifndef PORTAUDIO_H
#define PORTAUDIO_H #define PORTAUDIO_H
/* /*
* $Id: portaudio.h 1247 2007-08-11 16:29:09Z rossb $ * $Id: portaudio.h 1594 2011-02-05 14:33:29Z rossb $
* PortAudio Portable Real-Time Audio Library * PortAudio Portable Real-Time Audio Library
* PortAudio API Header File * PortAudio API Header File
* Latest version available at: http://www.portaudio.com/ * Latest version available at: http://www.portaudio.com/
* *
* Copyright (c) 1999-2002 Ross Bencina and Phil Burk * Copyright (c) 1999-2002 Ross Bencina and Phil Burk
* *
* Permission is hereby granted, free of charge, to any person obtaining * Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files * a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction, * (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, * including without limitation the rights to use, copy, modify, merge,
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* the PortAudio community also makes the following non-binding requests: * the PortAudio community also makes the following non-binding requests:
* *
* Any person wishing to distribute modifications to the Software is * Any person wishing to distribute modifications to the Software is
* requested to send the modifications to the original developer so that * requested to send the modifications to the original developer so that
* they can be incorporated into the canonical version. It is also * they can be incorporated into the canonical version. It is also
* requested that these non-binding requests be included along with the * requested that these non-binding requests be included along with the
* license above. * license above.
*/ */
/** @file /** @file
@brief The PortAudio API. @ingroup public_header
@brief The portable PortAudio API.
*/ */
#ifdef __cplusplus #ifdef __cplusplus
extern "C" extern "C"
{ {
#endif /* __cplusplus */ #endif /* __cplusplus */
/** Retrieve the release number of the currently running PortAudio build, /** Retrieve the release number of the currently running PortAudio build,
eg 1900. eg 1900.
*/ */
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paTimedOut, paTimedOut,
paInternalError, paInternalError,
paDeviceUnavailable, paDeviceUnavailable,
paIncompatibleHostApiSpecificStreamInfo, paIncompatibleHostApiSpecificStreamInfo,
paStreamIsStopped, paStreamIsStopped,
paStreamIsNotStopped, paStreamIsNotStopped,
paInputOverflowed, paInputOverflowed,
paOutputUnderflowed, paOutputUnderflowed,
paHostApiNotFound, paHostApiNotFound,
paInvalidHostApi, paInvalidHostApi,
paCanNotReadFromACallbackStream, /**< @todo review error code name paCanNotReadFromACallbackStream,
*/ paCanNotWriteToACallbackStream,
paCanNotWriteToACallbackStream, /**< @todo review error code name paCanNotReadFromAnOutputOnlyStream,
*/ paCanNotWriteToAnInputOnlyStream,
paCanNotReadFromAnOutputOnlyStream, /**< @todo review error code name
*/
paCanNotWriteToAnInputOnlyStream, /**< @todo review error code name
*/
paIncompatibleStreamHostApi, paIncompatibleStreamHostApi,
paBadBufferPtr paBadBufferPtr
} PaErrorCode; } PaErrorCode;
/** Translate the supplied PortAudio error code into a human readable /** Translate the supplied PortAudio error code into a human readable
message. message.
*/ */
const char *Pa_GetErrorText( PaError errorCode ); const char *Pa_GetErrorText( PaError errorCode );
/** Library initialization function - call this before using PortAudio. /** Library initialization function - call this before using PortAudio.
This function initialises internal data structures and prepares underlying This function initializes internal data structures and prepares underlying
host APIs for use. With the exception of Pa_GetVersion(), Pa_GetVersionTe xt(), host APIs for use. With the exception of Pa_GetVersion(), Pa_GetVersionTe xt(),
and Pa_GetErrorText(), this function MUST be called before using any other and Pa_GetErrorText(), this function MUST be called before using any other
PortAudio API functions. PortAudio API functions.
If Pa_Initialize() is called multiple times, each successful If Pa_Initialize() is called multiple times, each successful
call must be matched with a corresponding call to Pa_Terminate(). call must be matched with a corresponding call to Pa_Terminate().
Pairs of calls to Pa_Initialize()/Pa_Terminate() may overlap, and are not Pairs of calls to Pa_Initialize()/Pa_Terminate() may overlap, and are not
required to be fully nested. required to be fully nested.
Note that if Pa_Initialize() returns an error code, Pa_Terminate() should Note that if Pa_Initialize() returns an error code, Pa_Terminate() should
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@return paNoError if successful, otherwise an error code indicating the ca use @return paNoError if successful, otherwise an error code indicating the ca use
of failure. of failure.
@see Pa_Terminate @see Pa_Terminate
*/ */
PaError Pa_Initialize( void ); PaError Pa_Initialize( void );
/** Library termination function - call this when finished using PortAudio. /** Library termination function - call this when finished using PortAudio.
This function deallocates all resources allocated by PortAudio since it wa s This function deallocates all resources allocated by PortAudio since it wa s
initializied by a call to Pa_Initialize(). In cases where Pa_Initialise() has initialized by a call to Pa_Initialize(). In cases where Pa_Initialise() h as
been called multiple times, each call must be matched with a corresponding call been called multiple times, each call must be matched with a corresponding call
to Pa_Terminate(). The final matching call to Pa_Terminate() will automati cally to Pa_Terminate(). The final matching call to Pa_Terminate() will automati cally
close any PortAudio streams that are still open. close any PortAudio streams that are still open.
Pa_Terminate() MUST be called before exiting a program which uses PortAudi o. Pa_Terminate() MUST be called before exiting a program which uses PortAudi o.
Failure to do so may result in serious resource leaks, such as audio devic es Failure to do so may result in serious resource leaks, such as audio devic es
not being available until the next reboot. not being available until the next reboot.
@return paNoError if successful, otherwise an error code indicating the ca use @return paNoError if successful, otherwise an error code indicating the ca use
of failure. of failure.
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/** Structure used to return information about a host error condition. /** Structure used to return information about a host error condition.
*/ */
typedef struct PaHostErrorInfo{ typedef struct PaHostErrorInfo{
PaHostApiTypeId hostApiType; /**< the host API which returned the er ror code */ PaHostApiTypeId hostApiType; /**< the host API which returned the er ror code */
long errorCode; /**< the error code returned */ long errorCode; /**< the error code returned */
const char *errorText; /**< a textual description of the error if available, otherwise a zero-length string */ const char *errorText; /**< a textual description of the error if available, otherwise a zero-length string */
}PaHostErrorInfo; }PaHostErrorInfo;
/** Return information about the last host error encountered. The error /** Return information about the last host error encountered. The error
information returned by Pa_GetLastHostErrorInfo() will never be modified information returned by Pa_GetLastHostErrorInfo() will never be modified
asyncronously by errors occurring in other PortAudio owned threads asynchronously by errors occurring in other PortAudio owned threads
(such as the thread that manages the stream callback.) (such as the thread that manages the stream callback.)
This function is provided as a last resort, primarily to enhance debugging This function is provided as a last resort, primarily to enhance debugging
by providing clients with access to all available error information. by providing clients with access to all available error information.
@return A pointer to an immutable structure constaining information about @return A pointer to an immutable structure constraining information about
the host error. The values in this structure will only be valid if a the host error. The values in this structure will only be valid if a
PortAudio function has previously returned the paUnanticipatedHostError PortAudio function has previously returned the paUnanticipatedHostError
error code. error code.
*/ */
const PaHostErrorInfo* Pa_GetLastHostErrorInfo( void ); const PaHostErrorInfo* Pa_GetLastHostErrorInfo( void );
/* Device enumeration and capabilities */ /* Device enumeration and capabilities */
/** Retrieve the number of available devices. The number of available devic es /** Retrieve the number of available devices. The number of available devic es
may be zero. may be zero.
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used in the inputDevice parameter to Pa_OpenStream(). used in the inputDevice parameter to Pa_OpenStream().
@return The default input device index for the default host API, or paNoDe vice @return The default input device index for the default host API, or paNoDe vice
if no default input device is available or an error was encountered. if no default input device is available or an error was encountered.
*/ */
PaDeviceIndex Pa_GetDefaultInputDevice( void ); PaDeviceIndex Pa_GetDefaultInputDevice( void );
/** Retrieve the index of the default output device. The result can be /** Retrieve the index of the default output device. The result can be
used in the outputDevice parameter to Pa_OpenStream(). used in the outputDevice parameter to Pa_OpenStream().
@return The default output device index for the defualt host API, or paNoD evice @return The default output device index for the default host API, or paNoD evice
if no default output device is available or an error was encountered. if no default output device is available or an error was encountered.
@note @note
On the PC, the user can specify a default device by On the PC, the user can specify a default device by
setting an environment variable. For example, to use device #1. setting an environment variable. For example, to use device #1.
<pre> <pre>
set PA_RECOMMENDED_OUTPUT_DEVICE=1 set PA_RECOMMENDED_OUTPUT_DEVICE=1
</pre> </pre>
The user should first determine the available device ids by using The user should first determine the available device ids by using
the supplied application "pa_devs". the supplied application "pa_devs".
*/ */
PaDeviceIndex Pa_GetDefaultOutputDevice( void ); PaDeviceIndex Pa_GetDefaultOutputDevice( void );
/** The type used to represent monotonic time in seconds that can be used /** The type used to represent monotonic time in seconds. PaTime is
for syncronisation. The type is used for the outTime argument to the used for the fields of the PaStreamCallbackTimeInfo argument to the
PaStreamCallback and as the result of Pa_GetStreamTime(). PaStreamCallback and as the result of Pa_GetStreamTime().
@see PaStreamCallback, Pa_GetStreamTime PaTime values have unspecified origin.
@see PaStreamCallback, PaStreamCallbackTimeInfo, Pa_GetStreamTime
*/ */
typedef double PaTime; typedef double PaTime;
/** A type used to specify one or more sample formats. Each value indicates /** A type used to specify one or more sample formats. Each value indicates
a possible format for sound data passed to and from the stream callback, a possible format for sound data passed to and from the stream callback,
Pa_ReadStream and Pa_WriteStream. Pa_ReadStream and Pa_WriteStream.
The standard formats paFloat32, paInt16, paInt32, paInt24, paInt8 The standard formats paFloat32, paInt16, paInt32, paInt24, paInt8
and aUInt8 are usually implemented by all implementations. and aUInt8 are usually implemented by all implementations.
The floating point representation (paFloat32) uses +1.0 and -1.0 as the The floating point representation (paFloat32) uses +1.0 and -1.0 as the
maximum and minimum respectively. maximum and minimum respectively.
paUInt8 is an unsigned 8 bit format where 128 is considered "ground" paUInt8 is an unsigned 8 bit format where 128 is considered "ground"
The paNonInterleaved flag indicates that a multichannel buffer is passed The paNonInterleaved flag indicates that audio data is passed as an array
as a set of non-interleaved pointers. of pointers to separate buffers, one buffer for each channel. Usually,
when this flag is not used, audio data is passed as a single buffer with
all channels interleaved.
@see Pa_OpenStream, Pa_OpenDefaultStream, PaDeviceInfo @see Pa_OpenStream, Pa_OpenDefaultStream, PaDeviceInfo
@see paFloat32, paInt16, paInt32, paInt24, paInt8 @see paFloat32, paInt16, paInt32, paInt24, paInt8
@see paUInt8, paCustomFormat, paNonInterleaved @see paUInt8, paCustomFormat, paNonInterleaved
*/ */
typedef unsigned long PaSampleFormat; typedef unsigned long PaSampleFormat;
#define paFloat32 ((PaSampleFormat) 0x00000001) /**< @see PaSampleFo rmat */ #define paFloat32 ((PaSampleFormat) 0x00000001) /**< @see PaSampleFo rmat */
#define paInt32 ((PaSampleFormat) 0x00000002) /**< @see PaSampleFo rmat */ #define paInt32 ((PaSampleFormat) 0x00000002) /**< @see PaSampleFo rmat */
#define paInt24 ((PaSampleFormat) 0x00000004) /**< Packed 24 bit f ormat. @see PaSampleFormat */ #define paInt24 ((PaSampleFormat) 0x00000004) /**< Packed 24 bit f ormat. @see PaSampleFormat */
#define paInt16 ((PaSampleFormat) 0x00000008) /**< @see PaSampleFo rmat */ #define paInt16 ((PaSampleFormat) 0x00000008) /**< @see PaSampleFo rmat */
#define paInt8 ((PaSampleFormat) 0x00000010) /**< @see PaSampleFo rmat */ #define paInt8 ((PaSampleFormat) 0x00000010) /**< @see PaSampleFo rmat */
#define paUInt8 ((PaSampleFormat) 0x00000020) /**< @see PaSampleFo rmat */ #define paUInt8 ((PaSampleFormat) 0x00000020) /**< @see PaSampleFo rmat */
#define paCustomFormat ((PaSampleFormat) 0x00010000)/**< @see PaSampleFor mat */ #define paCustomFormat ((PaSampleFormat) 0x00010000) /**< @see PaSampleFo rmat */
#define paNonInterleaved ((PaSampleFormat) 0x80000000) #define paNonInterleaved ((PaSampleFormat) 0x80000000) /**< @see PaSampleFo rmat */
/** A structure providing information and capabilities of PortAudio devices . /** A structure providing information and capabilities of PortAudio devices .
Devices may support input, output or both input and output. Devices may support input, output or both input and output.
*/ */
typedef struct PaDeviceInfo typedef struct PaDeviceInfo
{ {
int structVersion; /* this is struct version 2 */ int structVersion; /* this is struct version 2 */
const char *name; const char *name;
PaHostApiIndex hostApi; /* note this is a host API index, not a type id */ PaHostApiIndex hostApi; /* note this is a host API index, not a type id */
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/** The sample format of the buffer provided to the stream callback, /** The sample format of the buffer provided to the stream callback,
a_ReadStream() or Pa_WriteStream(). It may be any of the formats descr ibed a_ReadStream() or Pa_WriteStream(). It may be any of the formats descr ibed
by the PaSampleFormat enumeration. by the PaSampleFormat enumeration.
*/ */
PaSampleFormat sampleFormat; PaSampleFormat sampleFormat;
/** The desired latency in seconds. Where practical, implementations sh ould /** The desired latency in seconds. Where practical, implementations sh ould
configure their latency based on these parameters, otherwise they may configure their latency based on these parameters, otherwise they may
choose the closest viable latency instead. Unless the suggested latenc y choose the closest viable latency instead. Unless the suggested latenc y
is greater than the absolute upper limit for the device implementation s is greater than the absolute upper limit for the device implementation s
should round the suggestedLatency up to the next practial value - ie t should round the suggestedLatency up to the next practical value - ie
o to
provide an equal or higher latency than suggestedLatency wherever poss provide an equal or higher latency than suggestedLatency wherever poss
ibe. ible.
Actual latency values for an open stream may be retrieved using the Actual latency values for an open stream may be retrieved using the
inputLatency and outputLatency fields of the PaStreamInfo structure inputLatency and outputLatency fields of the PaStreamInfo structure
returned by Pa_GetStreamInfo(). returned by Pa_GetStreamInfo().
@see default*Latency in PaDeviceInfo, *Latency in PaStreamInfo @see default*Latency in PaDeviceInfo, *Latency in PaStreamInfo
*/ */
PaTime suggestedLatency; PaTime suggestedLatency;
/** An optional pointer to a host api specific data structure /** An optional pointer to a host api specific data structure
containing additional information for device setup and/or stream proce ssing. containing additional information for device setup and/or stream proce ssing.
hostApiSpecificStreamInfo is never required for correct operation, hostApiSpecificStreamInfo is never required for correct operation,
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paContinue=0, paContinue=0,
paComplete=1, paComplete=1,
paAbort=2 paAbort=2
} PaStreamCallbackResult; } PaStreamCallbackResult;
/** /**
Functions of type PaStreamCallback are implemented by PortAudio clients. Functions of type PaStreamCallback are implemented by PortAudio clients.
They consume, process or generate audio in response to requests from an They consume, process or generate audio in response to requests from an
active PortAudio stream. active PortAudio stream.
@param input and @param output are arrays of interleaved samples, @param input and @param output are either arrays of interleaved samples or
the format, packing and number of channels used by the buffers are ;
if non-interleaved samples were requested using the paNonInterleaved sampl
e
format flag, an array of buffer pointers, one non-interleaved buffer for
each channel.
The format, packing and number of channels used by the buffers are
determined by parameters to Pa_OpenStream(). determined by parameters to Pa_OpenStream().
@param frameCount The number of sample frames to be processed by @param frameCount The number of sample frames to be processed by
the stream callback. the stream callback.
@param timeInfo The time in seconds when the first sample of the input @param timeInfo The time in seconds when the first sample of the input
buffer was received at the audio input, the time in seconds when the first buffer was received at the audio input, the time in seconds when the first
sample of the output buffer will begin being played at the audio output, a nd sample of the output buffer will begin being played at the audio output, a nd
the time in seconds when the stream callback was called. the time in seconds when the stream callback was called.
See also Pa_GetStreamTime() See also Pa_GetStreamTime()
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@return @return
The stream callback should return one of the values in the The stream callback should return one of the values in the
PaStreamCallbackResult enumeration. To ensure that the callback continues PaStreamCallbackResult enumeration. To ensure that the callback continues
to be called, it should return paContinue (0). Either paComplete or paAbor t to be called, it should return paContinue (0). Either paComplete or paAbor t
can be returned to finish stream processing, after either of these values is can be returned to finish stream processing, after either of these values is
returned the callback will not be called again. If paAbort is returned the returned the callback will not be called again. If paAbort is returned the
stream will finish as soon as possible. If paComplete is returned, the str eam stream will finish as soon as possible. If paComplete is returned, the str eam
will continue until all buffers generated by the callback have been played . will continue until all buffers generated by the callback have been played .
This may be useful in applications such as soundfile players where a speci fic This may be useful in applications such as soundfile players where a speci fic
duration of output is required. However, it is not necessary to utilise th is duration of output is required. However, it is not necessary to utilize th is
mechanism as Pa_StopStream(), Pa_AbortStream() or Pa_CloseStream() can als o mechanism as Pa_StopStream(), Pa_AbortStream() or Pa_CloseStream() can als o
be used to stop the stream. The callback must always fill the entire outpu t be used to stop the stream. The callback must always fill the entire outpu t
buffer irrespective of its return value. buffer irrespective of its return value.
@see Pa_OpenStream, Pa_OpenDefaultStream @see Pa_OpenStream, Pa_OpenDefaultStream
@note With the exception of Pa_GetStreamCpuLoad() it is not permissable to call @note With the exception of Pa_GetStreamCpuLoad() it is not permissible to call
PortAudio API functions from within the stream callback. PortAudio API functions from within the stream callback.
*/ */
typedef int PaStreamCallback( typedef int PaStreamCallback(
const void *input, void *output, const void *input, void *output,
unsigned long frameCount, unsigned long frameCount,
const PaStreamCallbackTimeInfo* timeInfo, const PaStreamCallbackTimeInfo* timeInfo,
PaStreamCallbackFlags statusFlags, PaStreamCallbackFlags statusFlags,
void *userData ); void *userData );
/** Opens a stream for either input, output or both. /** Opens a stream for either input, output or both.
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@param outputParameters A structure that describes the output parameters u sed by @param outputParameters A structure that describes the output parameters u sed by
the opened stream. See PaStreamParameters for a description of these param eters. the opened stream. See PaStreamParameters for a description of these param eters.
outputParameters must be NULL for input-only streams. outputParameters must be NULL for input-only streams.
@param sampleRate The desired sampleRate. For full-duplex streams it is th e @param sampleRate The desired sampleRate. For full-duplex streams it is th e
sample rate for both input and output sample rate for both input and output
@param framesPerBuffer The number of frames passed to the stream callback @param framesPerBuffer The number of frames passed to the stream callback
function, or the preferred block granularity for a blocking read/write str eam. function, or the preferred block granularity for a blocking read/write str eam.
The special value paFramesPerBufferUnspecified (0) may be used to request that The special value paFramesPerBufferUnspecified (0) may be used to request that
the stream callback will recieve an optimal (and possibly varying) number of the stream callback will receive an optimal (and possibly varying) number of
frames based on host requirements and the requested latency settings. frames based on host requirements and the requested latency settings.
Note: With some host APIs, the use of non-zero framesPerBuffer for a callb ack Note: With some host APIs, the use of non-zero framesPerBuffer for a callb ack
stream may introduce an additional layer of buffering which could introduc e stream may introduce an additional layer of buffering which could introduc e
additional latency. PortAudio guarantees that the additional latency additional latency. PortAudio guarantees that the additional latency
will be kept to the theoretical minimum however, it is strongly recommende d will be kept to the theoretical minimum however, it is strongly recommende d
that a non-zero framesPerBuffer value only be used when your algorithm that a non-zero framesPerBuffer value only be used when your algorithm
requires a fixed number of frames per stream callback. requires a fixed number of frames per stream callback.
@param streamFlags Flags which modify the behaviour of the streaming proce ss. @param streamFlags Flags which modify the behavior of the streaming proces s.
This parameter may contain a combination of flags ORed together. Some flag s may This parameter may contain a combination of flags ORed together. Some flag s may
only be relevant to certain buffer formats. only be relevant to certain buffer formats.
@param streamCallback A pointer to a client supplied function that is resp onsible @param streamCallback A pointer to a client supplied function that is resp onsible
for processing and filling input and output buffers. If this parameter is NULL for processing and filling input and output buffers. If this parameter is NULL
the stream will be opened in 'blocking read/write' mode. In blocking mode, the stream will be opened in 'blocking read/write' mode. In blocking mode,
the client can receive sample data using Pa_ReadStream and write sample da ta the client can receive sample data using Pa_ReadStream and write sample da ta
using Pa_WriteStream, the number of samples that may be read or written using Pa_WriteStream, the number of samples that may be read or written
without blocking is returned by Pa_GetStreamReadAvailable and without blocking is returned by Pa_GetStreamReadAvailable and
Pa_GetStreamWriteAvailable respectively. Pa_GetStreamWriteAvailable respectively.
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@param stream The address of a PaStream pointer which will receive @param stream The address of a PaStream pointer which will receive
a pointer to the newly opened stream. a pointer to the newly opened stream.
@param numInputChannels The number of channels of sound that will be supp lied @param numInputChannels The number of channels of sound that will be supp lied
to the stream callback or returned by Pa_ReadStream. It can range from 1 t o to the stream callback or returned by Pa_ReadStream. It can range from 1 t o
the value of maxInputChannels in the PaDeviceInfo record for the default i nput the value of maxInputChannels in the PaDeviceInfo record for the default i nput
device. If 0 the stream is opened as an output-only stream. device. If 0 the stream is opened as an output-only stream.
@param numOutputChannels The number of channels of sound to be delivered t o the @param numOutputChannels The number of channels of sound to be delivered t o the
stream callback or passed to Pa_WriteStream. It can range from 1 to the va lue stream callback or passed to Pa_WriteStream. It can range from 1 to the va lue
of maxOutputChannels in the PaDeviceInfo record for the default output dvi ce. of maxOutputChannels in the PaDeviceInfo record for the default output dev ice.
If 0 the stream is opened as an output-only stream. If 0 the stream is opened as an output-only stream.
@param sampleFormat The sample format of both the input and output buffers @param sampleFormat The sample format of both the input and output buffers
provided to the callback or passed to and from Pa_ReadStream and Pa_WriteS tream. provided to the callback or passed to and from Pa_ReadStream and Pa_WriteS tream.
sampleFormat may be any of the formats described by the PaSampleFormat sampleFormat may be any of the formats described by the PaSampleFormat
enumeration. enumeration.
@param sampleRate Same as Pa_OpenStream parameter of the same name. @param sampleRate Same as Pa_OpenStream parameter of the same name.
@param framesPerBuffer Same as Pa_OpenStream parameter of the same name. @param framesPerBuffer Same as Pa_OpenStream parameter of the same name.
@param streamCallback Same as Pa_OpenStream parameter of the same name. @param streamCallback Same as Pa_OpenStream parameter of the same name.
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@param stream A pointer to an open stream previously created with Pa_OpenS tream. @param stream A pointer to an open stream previously created with Pa_OpenS tream.
@note PortAudio manages the memory referenced by the returned pointer, @note PortAudio manages the memory referenced by the returned pointer,
the client must not manipulate or free the memory. The pointer is only the client must not manipulate or free the memory. The pointer is only
guaranteed to be valid until the specified stream is closed. guaranteed to be valid until the specified stream is closed.
@see PaStreamInfo @see PaStreamInfo
*/ */
const PaStreamInfo* Pa_GetStreamInfo( PaStream *stream ); const PaStreamInfo* Pa_GetStreamInfo( PaStream *stream );
/** Determine the current time for the stream according to the same clock u /** Returns the current time in seconds for a stream according to the same
sed clock used
to generate buffer timestamps. This time may be used for syncronising othe to generate callback PaStreamCallbackTimeInfo timestamps. The time values
r are
events to the audio stream, for example synchronizing audio to MIDI. monotonically increasing and have unspecified origin.
Pa_GetStreamTime returns valid time values for the entire life of the stre
am,
from when the stream is opened until it is closed. Starting and stopping t
he stream
does not affect the passage of time returned by Pa_GetStreamTime.
This time may be used for synchronizing other events to the audio stream,
for
example synchronizing audio to MIDI.
@return The stream's current time in seconds, or 0 if an error occurred. @return The stream's current time in seconds, or 0 if an error occurred.
@see PaTime, PaStreamCallback @see PaTime, PaStreamCallback, PaStreamCallbackTimeInfo
*/ */
PaTime Pa_GetStreamTime( PaStream *stream ); PaTime Pa_GetStreamTime( PaStream *stream );
/** Retrieve CPU usage information for the specified stream. /** Retrieve CPU usage information for the specified stream.
The "CPU Load" is a fraction of total CPU time consumed by a callback stre am's The "CPU Load" is a fraction of total CPU time consumed by a callback stre am's
audio processing routines including, but not limited to the client supplie d audio processing routines including, but not limited to the client supplie d
stream callback. This function does not work with blocking read/write stre ams. stream callback. This function does not work with blocking read/write stre ams.
This function may be called from the stream callback function or the This function may be called from the stream callback function or the
application. application.
@return @return
A floating point value, typically between 0.0 and 1.0, where 1.0 indicates A floating point value, typically between 0.0 and 1.0, where 1.0 indicates
that the stream callback is consuming the maximum number of CPU cycles pos sible that the stream callback is consuming the maximum number of CPU cycles pos sible
to maintain real-time operation. A value of 0.5 would imply that PortAudio and to maintain real-time operation. A value of 0.5 would imply that PortAudio and
the stream callback was consuming roughly 50% of the available CPU time. T he the stream callback was consuming roughly 50% of the available CPU time. T he
return value may exceed 1.0. A value of 0.0 will always be returned for a return value may exceed 1.0. A value of 0.0 will always be returned for a
blocking read/write stream, or if an error occurrs. blocking read/write stream, or if an error occurs.
*/ */
double Pa_GetStreamCpuLoad( PaStream* stream ); double Pa_GetStreamCpuLoad( PaStream* stream );
/** Read samples from an input stream. The function doesn't return until /** Read samples from an input stream. The function doesn't return until
the entire buffer has been filled - this may involve waiting for the opera ting the entire buffer has been filled - this may involve waiting for the opera ting
system to supply the data. system to supply the data.
@param stream A pointer to an open stream previously created with Pa_OpenS tream. @param stream A pointer to an open stream previously created with Pa_OpenS tream.
@param buffer A pointer to a buffer of sample frames. The buffer contains @param buffer A pointer to a buffer of sample frames. The buffer contains
samples in the format specified by the inputParameters->sampleFormat field samples in the format specified by the inputParameters->sampleFormat field
used to open the stream, and the number of channels specified by used to open the stream, and the number of channels specified by
inputParameters->numChannels. If non-interleaved samples were requested, inputParameters->numChannels. If non-interleaved samples were requested us
buffer is a pointer to the first element of an array of non-interleaved ing
buffer pointers, one for each channel. the paNonInterleaved sample format flag, buffer is a pointer to the first
element
of an array of buffer pointers, one non-interleaved buffer for each channe
l.
@param frames The number of frames to be read into buffer. This parameter @param frames The number of frames to be read into buffer. This parameter
is not constrained to a specific range, however high performance applicati ons is not constrained to a specific range, however high performance applicati ons
will want to match this parameter to the framesPerBuffer parameter used will want to match this parameter to the framesPerBuffer parameter used
when opening the stream. when opening the stream.
@return On success PaNoError will be returned, or PaInputOverflowed if inp ut @return On success PaNoError will be returned, or PaInputOverflowed if inp ut
data was discarded by PortAudio after the previous call and before this ca ll. data was discarded by PortAudio after the previous call and before this ca ll.
*/ */
PaError Pa_ReadStream( PaStream* stream, PaError Pa_ReadStream( PaStream* stream,
skipping to change at line 1012 skipping to change at line 1028
/** Write samples to an output stream. This function doesn't return until t he /** Write samples to an output stream. This function doesn't return until t he
entire buffer has been consumed - this may involve waiting for the operati ng entire buffer has been consumed - this may involve waiting for the operati ng
system to consume the data. system to consume the data.
@param stream A pointer to an open stream previously created with Pa_OpenS tream. @param stream A pointer to an open stream previously created with Pa_OpenS tream.
@param buffer A pointer to a buffer of sample frames. The buffer contains @param buffer A pointer to a buffer of sample frames. The buffer contains
samples in the format specified by the outputParameters->sampleFormat fiel d samples in the format specified by the outputParameters->sampleFormat fiel d
used to open the stream, and the number of channels specified by used to open the stream, and the number of channels specified by
outputParameters->numChannels. If non-interleaved samples were requested, outputParameters->numChannels. If non-interleaved samples were requested u
buffer is a pointer to the first element of an array of non-interleaved sing
buffer pointers, one for each channel. the paNonInterleaved sample format flag, buffer is a pointer to the first
element
of an array of buffer pointers, one non-interleaved buffer for each channe
l.
@param frames The number of frames to be written from buffer. This paramet er @param frames The number of frames to be written from buffer. This paramet er
is not constrained to a specific range, however high performance applicati ons is not constrained to a specific range, however high performance applicati ons
will want to match this parameter to the framesPerBuffer parameter used will want to match this parameter to the framesPerBuffer parameter used
when opening the stream. when opening the stream.
@return On success PaNoError will be returned, or paOutputUnderflowed if @return On success PaNoError will be returned, or paOutputUnderflowed if
additional output data was inserted after the previous call and before thi s additional output data was inserted after the previous call and before thi s
call. call.
*/ */
 End of changes. 25 change blocks. 
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