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* $Id: portaudio.h 1337 2008-02-15 07:32:09Z rossb $
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* PortAudio Portable Real-Time Audio Library
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* PortAudio API Header File
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* Latest version available at: http://www.portaudio.com/
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* Copyright (c) 1999-2002 Ross Bencina and Phil Burk
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files
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* (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge,
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* publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
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* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
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* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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* The text above constitutes the entire PortAudio license; however,
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* the PortAudio community also makes the following non-binding requests:
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* Any person wishing to distribute modifications to the Software is
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* requested to send the modifications to the original developer so that
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* they can be incorporated into the canonical version. It is also
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* requested that these non-binding requests be included along with the
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@ingroup public_header
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@brief The portable PortAudio API.
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#endif /* __cplusplus */
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/** Retrieve the release number of the currently running PortAudio build,
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int Pa_GetVersion( void );
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/** Retrieve a textual description of the current PortAudio build,
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eg "PortAudio V19-devel 13 October 2002".
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const char* Pa_GetVersionText( void );
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/** Error codes returned by PortAudio functions.
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Note that with the exception of paNoError, all PaErrorCodes are negative.
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typedef enum PaErrorCode
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paNotInitialized = -10000,
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paUnanticipatedHostError,
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paInvalidChannelCount,
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paSampleFormatNotSupported,
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paBadIODeviceCombination,
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paIncompatibleHostApiSpecificStreamInfo,
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paCanNotReadFromACallbackStream, /**< @todo review error code name */
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paCanNotWriteToACallbackStream, /**< @todo review error code name */
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paCanNotReadFromAnOutputOnlyStream, /**< @todo review error code name */
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paCanNotWriteToAnInputOnlyStream, /**< @todo review error code name */
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paIncompatibleStreamHostApi,
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/** Translate the supplied PortAudio error code into a human readable
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const char *Pa_GetErrorText( PaError errorCode );
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/** Library initialization function - call this before using PortAudio.
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This function initialises internal data structures and prepares underlying
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host APIs for use. With the exception of Pa_GetVersion(), Pa_GetVersionText(),
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and Pa_GetErrorText(), this function MUST be called before using any other
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PortAudio API functions.
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If Pa_Initialize() is called multiple times, each successful
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call must be matched with a corresponding call to Pa_Terminate().
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Pairs of calls to Pa_Initialize()/Pa_Terminate() may overlap, and are not
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required to be fully nested.
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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 cause
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PaError Pa_Initialize( void );
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/** Library termination function - call this when finished using PortAudio.
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This function deallocates all resources allocated by PortAudio since it was
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initializied by a call to Pa_Initialize(). In cases where Pa_Initialise() has
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been called multiple times, each call must be matched with a corresponding call
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to Pa_Terminate(). The final matching call to Pa_Terminate() will automatically
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close any PortAudio streams that are still open.
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Pa_Terminate() MUST be called before exiting a program which uses PortAudio.
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Failure to do so may result in serious resource leaks, such as audio devices
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not being available until the next reboot.
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@return paNoError if successful, otherwise an error code indicating the cause
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PaError Pa_Terminate( void );
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/** The type used to refer to audio devices. Values of this type usually
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range from 0 to (Pa_GetDeviceCount()-1), and may also take on the PaNoDevice
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and paUseHostApiSpecificDeviceSpecification values.
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@see Pa_GetDeviceCount, paNoDevice, paUseHostApiSpecificDeviceSpecification
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typedef int PaDeviceIndex;
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/** A special PaDeviceIndex value indicating that no device is available,
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#define paNoDevice ((PaDeviceIndex)-1)
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/** A special PaDeviceIndex value indicating that the device(s) to be used
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are specified in the host api specific stream info structure.
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#define paUseHostApiSpecificDeviceSpecification ((PaDeviceIndex)-2)
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/* Host API enumeration mechanism */
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/** The type used to enumerate to host APIs at runtime. Values of this type
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range from 0 to (Pa_GetHostApiCount()-1).
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@see Pa_GetHostApiCount
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typedef int PaHostApiIndex;
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/** Retrieve the number of available host APIs. Even if a host API is
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available it may have no devices available.
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@return A non-negative value indicating the number of available host APIs
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or, a PaErrorCode (which are always negative) if PortAudio is not initialized
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or an error is encountered.
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PaHostApiIndex Pa_GetHostApiCount( void );
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/** Retrieve the index of the default host API. The default host API will be
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the lowest common denominator host API on the current platform and is
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unlikely to provide the best performance.
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@return A non-negative value ranging from 0 to (Pa_GetHostApiCount()-1)
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indicating the default host API index or, a PaErrorCode (which are always
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negative) if PortAudio is not initialized or an error is encountered.
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PaHostApiIndex Pa_GetDefaultHostApi( void );
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/** Unchanging unique identifiers for each supported host API. This type
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is used in the PaHostApiInfo structure. The values are guaranteed to be
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unique and to never change, thus allowing code to be written that
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conditionally uses host API specific extensions.
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New type ids will be allocated when support for a host API reaches
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"public alpha" status, prior to that developers should use the
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paInDevelopment type id.
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typedef enum PaHostApiTypeId
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paInDevelopment=0, /* use while developing support for a new host API */
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/** A structure containing information about a particular host API. */
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typedef struct PaHostApiInfo
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/** this is struct version 1 */
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/** The well known unique identifier of this host API @see PaHostApiTypeId */
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PaHostApiTypeId type;
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/** A textual description of the host API for display on user interfaces. */
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/** The number of devices belonging to this host API. This field may be
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used in conjunction with Pa_HostApiDeviceIndexToDeviceIndex() to enumerate
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all devices for this host API.
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@see Pa_HostApiDeviceIndexToDeviceIndex
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/** The default input device for this host API. The value will be a
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device index ranging from 0 to (Pa_GetDeviceCount()-1), or paNoDevice
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if no default input device is available.
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PaDeviceIndex defaultInputDevice;
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/** The default output device for this host API. The value will be a
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device index ranging from 0 to (Pa_GetDeviceCount()-1), or paNoDevice
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if no default output device is available.
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PaDeviceIndex defaultOutputDevice;
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/** Retrieve a pointer to a structure containing information about a specific
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@param hostApi A valid host API index ranging from 0 to (Pa_GetHostApiCount()-1)
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@return A pointer to an immutable PaHostApiInfo structure describing
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a specific host API. If the hostApi parameter is out of range or an error
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is encountered, the function returns NULL.
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The returned structure is owned by the PortAudio implementation and must not
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be manipulated or freed. The pointer is only guaranteed to be valid between
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calls to Pa_Initialize() and Pa_Terminate().
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const PaHostApiInfo * Pa_GetHostApiInfo( PaHostApiIndex hostApi );
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/** Convert a static host API unique identifier, into a runtime
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@param type A unique host API identifier belonging to the PaHostApiTypeId
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@return A valid PaHostApiIndex ranging from 0 to (Pa_GetHostApiCount()-1) or,
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a PaErrorCode (which are always negative) if PortAudio is not initialized
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or an error is encountered.
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The paHostApiNotFound error code indicates that the host API specified by the
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type parameter is not available.
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PaHostApiIndex Pa_HostApiTypeIdToHostApiIndex( PaHostApiTypeId type );
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/** Convert a host-API-specific device index to standard PortAudio device index.
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This function may be used in conjunction with the deviceCount field of
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PaHostApiInfo to enumerate all devices for the specified host API.
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@param hostApi A valid host API index ranging from 0 to (Pa_GetHostApiCount()-1)
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@param hostApiDeviceIndex A valid per-host device index in the range
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0 to (Pa_GetHostApiInfo(hostApi)->deviceCount-1)
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@return A non-negative PaDeviceIndex ranging from 0 to (Pa_GetDeviceCount()-1)
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or, a PaErrorCode (which are always negative) if PortAudio is not initialized
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or an error is encountered.
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A paInvalidHostApi error code indicates that the host API index specified by
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the hostApi parameter is out of range.
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A paInvalidDevice error code indicates that the hostApiDeviceIndex parameter
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PaDeviceIndex Pa_HostApiDeviceIndexToDeviceIndex( PaHostApiIndex hostApi,
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int hostApiDeviceIndex );
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/** Structure used to return information about a host error condition.
338
typedef struct PaHostErrorInfo{
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PaHostApiTypeId hostApiType; /**< the host API which returned the error code */
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long errorCode; /**< the error code returned */
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const char *errorText; /**< a textual description of the error if available, otherwise a zero-length string */
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/** Return information about the last host error encountered. The error
346
information returned by Pa_GetLastHostErrorInfo() will never be modified
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asyncronously by errors occurring in other PortAudio owned threads
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(such as the thread that manages the stream callback.)
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This function is provided as a last resort, primarily to enhance debugging
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by providing clients with access to all available error information.
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@return A pointer to an immutable structure constaining information about
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the host error. The values in this structure will only be valid if a
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PortAudio function has previously returned the paUnanticipatedHostError
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const PaHostErrorInfo* Pa_GetLastHostErrorInfo( void );
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/* Device enumeration and capabilities */
364
/** Retrieve the number of available devices. The number of available devices
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@return A non-negative value indicating the number of available devices or,
368
a PaErrorCode (which are always negative) if PortAudio is not initialized
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or an error is encountered.
371
PaDeviceIndex Pa_GetDeviceCount( void );
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/** Retrieve the index of the default input device. The result can be
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used in the inputDevice parameter to Pa_OpenStream().
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@return The default input device index for the default host API, or paNoDevice
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if no default input device is available or an error was encountered.
380
PaDeviceIndex Pa_GetDefaultInputDevice( void );
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/** Retrieve the index of the default output device. The result can be
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used in the outputDevice parameter to Pa_OpenStream().
386
@return The default output device index for the defualt host API, or paNoDevice
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if no default output device is available or an error was encountered.
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On the PC, the user can specify a default device by
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setting an environment variable. For example, to use device #1.
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set PA_RECOMMENDED_OUTPUT_DEVICE=1
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The user should first determine the available device ids by using
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the supplied application "pa_devs".
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PaDeviceIndex Pa_GetDefaultOutputDevice( void );
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/** The type used to represent monotonic time in seconds that can be used
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for syncronisation. The type is used for the outTime argument to the
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PaStreamCallback and as the result of Pa_GetStreamTime().
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@see PaStreamCallback, Pa_GetStreamTime
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typedef double PaTime;
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/** A type used to specify one or more sample formats. Each value indicates
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a possible format for sound data passed to and from the stream callback,
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Pa_ReadStream and Pa_WriteStream.
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The standard formats paFloat32, paInt16, paInt32, paInt24, paInt8
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and aUInt8 are usually implemented by all implementations.
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The floating point representation (paFloat32) uses +1.0 and -1.0 as the
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maximum and minimum respectively.
420
paUInt8 is an unsigned 8 bit format where 128 is considered "ground"
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The paNonInterleaved flag indicates that a multichannel buffer is passed
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as a set of non-interleaved pointers.
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@see Pa_OpenStream, Pa_OpenDefaultStream, PaDeviceInfo
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@see paFloat32, paInt16, paInt32, paInt24, paInt8
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@see paUInt8, paCustomFormat, paNonInterleaved
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typedef unsigned long PaSampleFormat;
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#define paFloat32 ((PaSampleFormat) 0x00000001) /**< @see PaSampleFormat */
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#define paInt32 ((PaSampleFormat) 0x00000002) /**< @see PaSampleFormat */
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#define paInt24 ((PaSampleFormat) 0x00000004) /**< Packed 24 bit format. @see PaSampleFormat */
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#define paInt16 ((PaSampleFormat) 0x00000008) /**< @see PaSampleFormat */
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#define paInt8 ((PaSampleFormat) 0x00000010) /**< @see PaSampleFormat */
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#define paUInt8 ((PaSampleFormat) 0x00000020) /**< @see PaSampleFormat */
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#define paCustomFormat ((PaSampleFormat) 0x00010000)/**< @see PaSampleFormat */
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#define paNonInterleaved ((PaSampleFormat) 0x80000000)
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/** A structure providing information and capabilities of PortAudio devices.
443
Devices may support input, output or both input and output.
445
typedef struct PaDeviceInfo
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int structVersion; /* this is struct version 2 */
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PaHostApiIndex hostApi; /* note this is a host API index, not a type id*/
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int maxInputChannels;
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int maxOutputChannels;
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/* Default latency values for interactive performance. */
455
PaTime defaultLowInputLatency;
456
PaTime defaultLowOutputLatency;
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/* Default latency values for robust non-interactive applications (eg. playing sound files). */
458
PaTime defaultHighInputLatency;
459
PaTime defaultHighOutputLatency;
461
double defaultSampleRate;
465
/** Retrieve a pointer to a PaDeviceInfo structure containing information
466
about the specified device.
467
@return A pointer to an immutable PaDeviceInfo structure. If the device
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parameter is out of range the function returns NULL.
470
@param device A valid device index in the range 0 to (Pa_GetDeviceCount()-1)
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@note PortAudio manages the memory referenced by the returned pointer,
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the client must not manipulate or free the memory. The pointer is only
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guaranteed to be valid between calls to Pa_Initialize() and Pa_Terminate().
476
@see PaDeviceInfo, PaDeviceIndex
478
const PaDeviceInfo* Pa_GetDeviceInfo( PaDeviceIndex device );
481
/** Parameters for one direction (input or output) of a stream.
483
typedef struct PaStreamParameters
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/** A valid device index in the range 0 to (Pa_GetDeviceCount()-1)
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specifying the device to be used or the special constant
487
paUseHostApiSpecificDeviceSpecification which indicates that the actual
488
device(s) to use are specified in hostApiSpecificStreamInfo.
489
This field must not be set to paNoDevice.
491
PaDeviceIndex device;
493
/** The number of channels of sound to be delivered to the
494
stream callback or accessed by Pa_ReadStream() or Pa_WriteStream().
495
It can range from 1 to the value of maxInputChannels in the
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PaDeviceInfo record for the device specified by the device parameter.
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/** The sample format of the buffer provided to the stream callback,
501
a_ReadStream() or Pa_WriteStream(). It may be any of the formats described
502
by the PaSampleFormat enumeration.
504
PaSampleFormat sampleFormat;
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/** The desired latency in seconds. Where practical, implementations should
507
configure their latency based on these parameters, otherwise they may
508
choose the closest viable latency instead. Unless the suggested latency
509
is greater than the absolute upper limit for the device implementations
510
should round the suggestedLatency up to the next practial value - ie to
511
provide an equal or higher latency than suggestedLatency wherever possibe.
512
Actual latency values for an open stream may be retrieved using the
513
inputLatency and outputLatency fields of the PaStreamInfo structure
514
returned by Pa_GetStreamInfo().
515
@see default*Latency in PaDeviceInfo, *Latency in PaStreamInfo
517
PaTime suggestedLatency;
519
/** An optional pointer to a host api specific data structure
520
containing additional information for device setup and/or stream processing.
521
hostApiSpecificStreamInfo is never required for correct operation,
522
if not used it should be set to NULL.
524
void *hostApiSpecificStreamInfo;
526
} PaStreamParameters;
529
/** Return code for Pa_IsFormatSupported indicating success. */
530
#define paFormatIsSupported (0)
532
/** Determine whether it would be possible to open a stream with the specified
535
@param inputParameters A structure that describes the input parameters used to
536
open a stream. The suggestedLatency field is ignored. See PaStreamParameters
537
for a description of these parameters. inputParameters must be NULL for
540
@param outputParameters A structure that describes the output parameters used
541
to open a stream. The suggestedLatency field is ignored. See PaStreamParameters
542
for a description of these parameters. outputParameters must be NULL for
545
@param sampleRate The required sampleRate. For full-duplex streams it is the
546
sample rate for both input and output
548
@return Returns 0 if the format is supported, and an error code indicating why
549
the format is not supported otherwise. The constant paFormatIsSupported is
550
provided to compare with the return value for success.
552
@see paFormatIsSupported, PaStreamParameters
554
PaError Pa_IsFormatSupported( const PaStreamParameters *inputParameters,
555
const PaStreamParameters *outputParameters,
560
/* Streaming types and functions */
564
A single PaStream can provide multiple channels of real-time
565
streaming audio input and output to a client application. A stream
566
provides access to audio hardware represented by one or more
567
PaDevices. Depending on the underlying Host API, it may be possible
568
to open multiple streams using the same device, however this behavior
569
is implementation defined. Portable applications should assume that
570
a PaDevice may be simultaneously used by at most one PaStream.
572
Pointers to PaStream objects are passed between PortAudio functions that
575
@see Pa_OpenStream, Pa_OpenDefaultStream, Pa_OpenDefaultStream, Pa_CloseStream,
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Pa_StartStream, Pa_StopStream, Pa_AbortStream, Pa_IsStreamActive,
577
Pa_GetStreamTime, Pa_GetStreamCpuLoad
580
typedef void PaStream;
583
/** Can be passed as the framesPerBuffer parameter to Pa_OpenStream()
584
or Pa_OpenDefaultStream() to indicate that the stream callback will
585
accept buffers of any size.
587
#define paFramesPerBufferUnspecified (0)
590
/** Flags used to control the behavior of a stream. They are passed as
591
parameters to Pa_OpenStream or Pa_OpenDefaultStream. Multiple flags may be
594
@see Pa_OpenStream, Pa_OpenDefaultStream
595
@see paNoFlag, paClipOff, paDitherOff, paNeverDropInput,
596
paPrimeOutputBuffersUsingStreamCallback, paPlatformSpecificFlags
598
typedef unsigned long PaStreamFlags;
600
/** @see PaStreamFlags */
601
#define paNoFlag ((PaStreamFlags) 0)
603
/** Disable default clipping of out of range samples.
606
#define paClipOff ((PaStreamFlags) 0x00000001)
608
/** Disable default dithering.
611
#define paDitherOff ((PaStreamFlags) 0x00000002)
613
/** Flag requests that where possible a full duplex stream will not discard
614
overflowed input samples without calling the stream callback. This flag is
615
only valid for full duplex callback streams and only when used in combination
616
with the paFramesPerBufferUnspecified (0) framesPerBuffer parameter. Using
617
this flag incorrectly results in a paInvalidFlag error being returned from
618
Pa_OpenStream and Pa_OpenDefaultStream.
620
@see PaStreamFlags, paFramesPerBufferUnspecified
622
#define paNeverDropInput ((PaStreamFlags) 0x00000004)
624
/** Call the stream callback to fill initial output buffers, rather than the
625
default behavior of priming the buffers with zeros (silence). This flag has
626
no effect for input-only and blocking read/write streams.
630
#define paPrimeOutputBuffersUsingStreamCallback ((PaStreamFlags) 0x00000008)
632
/** A mask specifying the platform specific bits.
635
#define paPlatformSpecificFlags ((PaStreamFlags)0xFFFF0000)
638
Timing information for the buffers passed to the stream callback.
640
typedef struct PaStreamCallbackTimeInfo{
641
PaTime inputBufferAdcTime;
643
PaTime outputBufferDacTime;
644
} PaStreamCallbackTimeInfo;
648
Flag bit constants for the statusFlags to PaStreamCallback.
650
@see paInputUnderflow, paInputOverflow, paOutputUnderflow, paOutputOverflow,
653
typedef unsigned long PaStreamCallbackFlags;
655
/** In a stream opened with paFramesPerBufferUnspecified, indicates that
656
input data is all silence (zeros) because no real data is available. In a
657
stream opened without paFramesPerBufferUnspecified, it indicates that one or
658
more zero samples have been inserted into the input buffer to compensate
659
for an input underflow.
660
@see PaStreamCallbackFlags
662
#define paInputUnderflow ((PaStreamCallbackFlags) 0x00000001)
664
/** In a stream opened with paFramesPerBufferUnspecified, indicates that data
665
prior to the first sample of the input buffer was discarded due to an
666
overflow, possibly because the stream callback is using too much CPU time.
667
Otherwise indicates that data prior to one or more samples in the
668
input buffer was discarded.
669
@see PaStreamCallbackFlags
671
#define paInputOverflow ((PaStreamCallbackFlags) 0x00000002)
673
/** Indicates that output data (or a gap) was inserted, possibly because the
674
stream callback is using too much CPU time.
675
@see PaStreamCallbackFlags
677
#define paOutputUnderflow ((PaStreamCallbackFlags) 0x00000004)
679
/** Indicates that output data will be discarded because no room is available.
680
@see PaStreamCallbackFlags
682
#define paOutputOverflow ((PaStreamCallbackFlags) 0x00000008)
684
/** Some of all of the output data will be used to prime the stream, input
686
@see PaStreamCallbackFlags
688
#define paPrimingOutput ((PaStreamCallbackFlags) 0x00000010)
691
Allowable return values for the PaStreamCallback.
692
@see PaStreamCallback
694
typedef enum PaStreamCallbackResult
699
} PaStreamCallbackResult;
703
Functions of type PaStreamCallback are implemented by PortAudio clients.
704
They consume, process or generate audio in response to requests from an
705
active PortAudio stream.
707
@param input and @param output are arrays of interleaved samples,
708
the format, packing and number of channels used by the buffers are
709
determined by parameters to Pa_OpenStream().
711
@param frameCount The number of sample frames to be processed by
714
@param timeInfo The time in seconds when the first sample of the input
715
buffer was received at the audio input, the time in seconds when the first
716
sample of the output buffer will begin being played at the audio output, and
717
the time in seconds when the stream callback was called.
718
See also Pa_GetStreamTime()
720
@param statusFlags Flags indicating whether input and/or output buffers
721
have been inserted or will be dropped to overcome underflow or overflow
724
@param userData The value of a user supplied pointer passed to
725
Pa_OpenStream() intended for storing synthesis data etc.
728
The stream callback should return one of the values in the
729
PaStreamCallbackResult enumeration. To ensure that the callback continues
730
to be called, it should return paContinue (0). Either paComplete or paAbort
731
can be returned to finish stream processing, after either of these values is
732
returned the callback will not be called again. If paAbort is returned the
733
stream will finish as soon as possible. If paComplete is returned, the stream
734
will continue until all buffers generated by the callback have been played.
735
This may be useful in applications such as soundfile players where a specific
736
duration of output is required. However, it is not necessary to utilise this
737
mechanism as Pa_StopStream(), Pa_AbortStream() or Pa_CloseStream() can also
738
be used to stop the stream. The callback must always fill the entire output
739
buffer irrespective of its return value.
741
@see Pa_OpenStream, Pa_OpenDefaultStream
743
@note With the exception of Pa_GetStreamCpuLoad() it is not permissable to call
744
PortAudio API functions from within the stream callback.
746
typedef int PaStreamCallback(
747
const void *input, void *output,
748
unsigned long frameCount,
749
const PaStreamCallbackTimeInfo* timeInfo,
750
PaStreamCallbackFlags statusFlags,
754
/** Opens a stream for either input, output or both.
756
@param stream The address of a PaStream pointer which will receive
757
a pointer to the newly opened stream.
759
@param inputParameters A structure that describes the input parameters used by
760
the opened stream. See PaStreamParameters for a description of these parameters.
761
inputParameters must be NULL for output-only streams.
763
@param outputParameters A structure that describes the output parameters used by
764
the opened stream. See PaStreamParameters for a description of these parameters.
765
outputParameters must be NULL for input-only streams.
767
@param sampleRate The desired sampleRate. For full-duplex streams it is the
768
sample rate for both input and output
770
@param framesPerBuffer The number of frames passed to the stream callback
771
function, or the preferred block granularity for a blocking read/write stream.
772
The special value paFramesPerBufferUnspecified (0) may be used to request that
773
the stream callback will recieve an optimal (and possibly varying) number of
774
frames based on host requirements and the requested latency settings.
775
Note: With some host APIs, the use of non-zero framesPerBuffer for a callback
776
stream may introduce an additional layer of buffering which could introduce
777
additional latency. PortAudio guarantees that the additional latency
778
will be kept to the theoretical minimum however, it is strongly recommended
779
that a non-zero framesPerBuffer value only be used when your algorithm
780
requires a fixed number of frames per stream callback.
782
@param streamFlags Flags which modify the behaviour of the streaming process.
783
This parameter may contain a combination of flags ORed together. Some flags may
784
only be relevant to certain buffer formats.
786
@param streamCallback A pointer to a client supplied function that is responsible
787
for processing and filling input and output buffers. If this parameter is NULL
788
the stream will be opened in 'blocking read/write' mode. In blocking mode,
789
the client can receive sample data using Pa_ReadStream and write sample data
790
using Pa_WriteStream, the number of samples that may be read or written
791
without blocking is returned by Pa_GetStreamReadAvailable and
792
Pa_GetStreamWriteAvailable respectively.
794
@param userData A client supplied pointer which is passed to the stream callback
795
function. It could for example, contain a pointer to instance data necessary
796
for processing the audio buffers. This parameter is ignored if streamCallback
800
Upon success Pa_OpenStream() returns paNoError and places a pointer to a
801
valid PaStream in the stream argument. The stream is inactive (stopped).
802
If a call to Pa_OpenStream() fails, a non-zero error code is returned (see
803
PaError for possible error codes) and the value of stream is invalid.
805
@see PaStreamParameters, PaStreamCallback, Pa_ReadStream, Pa_WriteStream,
806
Pa_GetStreamReadAvailable, Pa_GetStreamWriteAvailable
808
PaError Pa_OpenStream( PaStream** stream,
809
const PaStreamParameters *inputParameters,
810
const PaStreamParameters *outputParameters,
812
unsigned long framesPerBuffer,
813
PaStreamFlags streamFlags,
814
PaStreamCallback *streamCallback,
818
/** A simplified version of Pa_OpenStream() that opens the default input
819
and/or output devices.
821
@param stream The address of a PaStream pointer which will receive
822
a pointer to the newly opened stream.
824
@param numInputChannels The number of channels of sound that will be supplied
825
to the stream callback or returned by Pa_ReadStream. It can range from 1 to
826
the value of maxInputChannels in the PaDeviceInfo record for the default input
827
device. If 0 the stream is opened as an output-only stream.
829
@param numOutputChannels The number of channels of sound to be delivered to the
830
stream callback or passed to Pa_WriteStream. It can range from 1 to the value
831
of maxOutputChannels in the PaDeviceInfo record for the default output dvice.
832
If 0 the stream is opened as an output-only stream.
834
@param sampleFormat The sample format of both the input and output buffers
835
provided to the callback or passed to and from Pa_ReadStream and Pa_WriteStream.
836
sampleFormat may be any of the formats described by the PaSampleFormat
839
@param sampleRate Same as Pa_OpenStream parameter of the same name.
840
@param framesPerBuffer Same as Pa_OpenStream parameter of the same name.
841
@param streamCallback Same as Pa_OpenStream parameter of the same name.
842
@param userData Same as Pa_OpenStream parameter of the same name.
844
@return As for Pa_OpenStream
846
@see Pa_OpenStream, PaStreamCallback
848
PaError Pa_OpenDefaultStream( PaStream** stream,
849
int numInputChannels,
850
int numOutputChannels,
851
PaSampleFormat sampleFormat,
853
unsigned long framesPerBuffer,
854
PaStreamCallback *streamCallback,
858
/** Closes an audio stream. If the audio stream is active it
859
discards any pending buffers as if Pa_AbortStream() had been called.
861
PaError Pa_CloseStream( PaStream *stream );
864
/** Functions of type PaStreamFinishedCallback are implemented by PortAudio
865
clients. They can be registered with a stream using the Pa_SetStreamFinishedCallback
866
function. Once registered they are called when the stream becomes inactive
867
(ie once a call to Pa_StopStream() will not block).
868
A stream will become inactive after the stream callback returns non-zero,
869
or when Pa_StopStream or Pa_AbortStream is called. For a stream providing audio
870
output, if the stream callback returns paComplete, or Pa_StopStream is called,
871
the stream finished callback will not be called until all generated sample data
874
@param userData The userData parameter supplied to Pa_OpenStream()
876
@see Pa_SetStreamFinishedCallback
878
typedef void PaStreamFinishedCallback( void *userData );
881
/** Register a stream finished callback function which will be called when the
882
stream becomes inactive. See the description of PaStreamFinishedCallback for
883
further details about when the callback will be called.
885
@param stream a pointer to a PaStream that is in the stopped state - if the
886
stream is not stopped, the stream's finished callback will remain unchanged
887
and an error code will be returned.
889
@param streamFinishedCallback a pointer to a function with the same signature
890
as PaStreamFinishedCallback, that will be called when the stream becomes
891
inactive. Passing NULL for this parameter will un-register a previously
892
registered stream finished callback function.
894
@return on success returns paNoError, otherwise an error code indicating the cause
897
@see PaStreamFinishedCallback
899
PaError Pa_SetStreamFinishedCallback( PaStream *stream, PaStreamFinishedCallback* streamFinishedCallback );
902
/** Commences audio processing.
904
PaError Pa_StartStream( PaStream *stream );
907
/** Terminates audio processing. It waits until all pending
908
audio buffers have been played before it returns.
910
PaError Pa_StopStream( PaStream *stream );
913
/** Terminates audio processing immediately without waiting for pending
916
PaError Pa_AbortStream( PaStream *stream );
919
/** Determine whether the stream is stopped.
920
A stream is considered to be stopped prior to a successful call to
921
Pa_StartStream and after a successful call to Pa_StopStream or Pa_AbortStream.
922
If a stream callback returns a value other than paContinue the stream is NOT
923
considered to be stopped.
925
@return Returns one (1) when the stream is stopped, zero (0) when
926
the stream is running or, a PaErrorCode (which are always negative) if
927
PortAudio is not initialized or an error is encountered.
929
@see Pa_StopStream, Pa_AbortStream, Pa_IsStreamActive
931
PaError Pa_IsStreamStopped( PaStream *stream );
934
/** Determine whether the stream is active.
935
A stream is active after a successful call to Pa_StartStream(), until it
936
becomes inactive either as a result of a call to Pa_StopStream() or
937
Pa_AbortStream(), or as a result of a return value other than paContinue from
938
the stream callback. In the latter case, the stream is considered inactive
939
after the last buffer has finished playing.
941
@return Returns one (1) when the stream is active (ie playing or recording
942
audio), zero (0) when not playing or, a PaErrorCode (which are always negative)
943
if PortAudio is not initialized or an error is encountered.
945
@see Pa_StopStream, Pa_AbortStream, Pa_IsStreamStopped
947
PaError Pa_IsStreamActive( PaStream *stream );
951
/** A structure containing unchanging information about an open stream.
952
@see Pa_GetStreamInfo
955
typedef struct PaStreamInfo
957
/** this is struct version 1 */
960
/** The input latency of the stream in seconds. This value provides the most
961
accurate estimate of input latency available to the implementation. It may
962
differ significantly from the suggestedLatency value passed to Pa_OpenStream().
963
The value of this field will be zero (0.) for output-only streams.
968
/** The output latency of the stream in seconds. This value provides the most
969
accurate estimate of output latency available to the implementation. It may
970
differ significantly from the suggestedLatency value passed to Pa_OpenStream().
971
The value of this field will be zero (0.) for input-only streams.
974
PaTime outputLatency;
976
/** The sample rate of the stream in Hertz (samples per second). In cases
977
where the hardware sample rate is inaccurate and PortAudio is aware of it,
978
the value of this field may be different from the sampleRate parameter
979
passed to Pa_OpenStream(). If information about the actual hardware sample
980
rate is not available, this field will have the same value as the sampleRate
981
parameter passed to Pa_OpenStream().
988
/** Retrieve a pointer to a PaStreamInfo structure containing information
989
about the specified stream.
990
@return A pointer to an immutable PaStreamInfo structure. If the stream
991
parameter invalid, or an error is encountered, the function returns NULL.
993
@param stream A pointer to an open stream previously created with Pa_OpenStream.
995
@note PortAudio manages the memory referenced by the returned pointer,
996
the client must not manipulate or free the memory. The pointer is only
997
guaranteed to be valid until the specified stream is closed.
1001
const PaStreamInfo* Pa_GetStreamInfo( PaStream *stream );
1004
/** Determine the current time for the stream according to the same clock used
1005
to generate buffer timestamps. This time may be used for syncronising other
1006
events to the audio stream, for example synchronizing audio to MIDI.
1008
@return The stream's current time in seconds, or 0 if an error occurred.
1010
@see PaTime, PaStreamCallback
1012
PaTime Pa_GetStreamTime( PaStream *stream );
1015
/** Retrieve CPU usage information for the specified stream.
1016
The "CPU Load" is a fraction of total CPU time consumed by a callback stream's
1017
audio processing routines including, but not limited to the client supplied
1018
stream callback. This function does not work with blocking read/write streams.
1020
This function may be called from the stream callback function or the
1024
A floating point value, typically between 0.0 and 1.0, where 1.0 indicates
1025
that the stream callback is consuming the maximum number of CPU cycles possible
1026
to maintain real-time operation. A value of 0.5 would imply that PortAudio and
1027
the stream callback was consuming roughly 50% of the available CPU time. The
1028
return value may exceed 1.0. A value of 0.0 will always be returned for a
1029
blocking read/write stream, or if an error occurrs.
1031
double Pa_GetStreamCpuLoad( PaStream* stream );
1034
/** Read samples from an input stream. The function doesn't return until
1035
the entire buffer has been filled - this may involve waiting for the operating
1036
system to supply the data.
1038
@param stream A pointer to an open stream previously created with Pa_OpenStream.
1040
@param buffer A pointer to a buffer of sample frames. The buffer contains
1041
samples in the format specified by the inputParameters->sampleFormat field
1042
used to open the stream, and the number of channels specified by
1043
inputParameters->numChannels. If non-interleaved samples were requested,
1044
buffer is a pointer to the first element of an array of non-interleaved
1045
buffer pointers, one for each channel.
1047
@param frames The number of frames to be read into buffer. This parameter
1048
is not constrained to a specific range, however high performance applications
1049
will want to match this parameter to the framesPerBuffer parameter used
1050
when opening the stream.
1052
@return On success PaNoError will be returned, or PaInputOverflowed if input
1053
data was discarded by PortAudio after the previous call and before this call.
1055
PaError Pa_ReadStream( PaStream* stream,
1057
unsigned long frames );
1060
/** Write samples to an output stream. This function doesn't return until the
1061
entire buffer has been consumed - this may involve waiting for the operating
1062
system to consume the data.
1064
@param stream A pointer to an open stream previously created with Pa_OpenStream.
1066
@param buffer A pointer to a buffer of sample frames. The buffer contains
1067
samples in the format specified by the outputParameters->sampleFormat field
1068
used to open the stream, and the number of channels specified by
1069
outputParameters->numChannels. If non-interleaved samples were requested,
1070
buffer is a pointer to the first element of an array of non-interleaved
1071
buffer pointers, one for each channel.
1073
@param frames The number of frames to be written from buffer. This parameter
1074
is not constrained to a specific range, however high performance applications
1075
will want to match this parameter to the framesPerBuffer parameter used
1076
when opening the stream.
1078
@return On success PaNoError will be returned, or paOutputUnderflowed if
1079
additional output data was inserted after the previous call and before this
1082
PaError Pa_WriteStream( PaStream* stream,
1084
unsigned long frames );
1087
/** Retrieve the number of frames that can be read from the stream without
1090
@return Returns a non-negative value representing the maximum number of frames
1091
that can be read from the stream without blocking or busy waiting or, a
1092
PaErrorCode (which are always negative) if PortAudio is not initialized or an
1093
error is encountered.
1095
signed long Pa_GetStreamReadAvailable( PaStream* stream );
1098
/** Retrieve the number of frames that can be written to the stream without
1101
@return Returns a non-negative value representing the maximum number of frames
1102
that can be written to the stream without blocking or busy waiting or, a
1103
PaErrorCode (which are always negative) if PortAudio is not initialized or an
1104
error is encountered.
1106
signed long Pa_GetStreamWriteAvailable( PaStream* stream );
1109
/* Miscellaneous utilities */
1112
/** Retrieve the size of a given sample format in bytes.
1114
@return The size in bytes of a single sample in the specified format,
1115
or paSampleFormatNotSupported if the format is not supported.
1117
PaError Pa_GetSampleSize( PaSampleFormat format );
1120
/** Put the caller to sleep for at least 'msec' milliseconds. This function is
1121
provided only as a convenience for authors of portable code (such as the tests
1122
and examples in the PortAudio distribution.)
1124
The function may sleep longer than requested so don't rely on this for accurate
1127
void Pa_Sleep( long msec );
1133
#endif /* __cplusplus */
1134
#endif /* PORTAUDIO_H */