Help me with callback funcion.

From:
"Solang" <solang@verizon.net>
Newsgroups:
comp.lang.c++
Date:
Thu, 24 Sep 2009 18:09:36 GMT
Message-ID:
<ABOum.3211$Jd7.1810@nwrddc02.gnilink.net>
Hi Everyone,

    I am trying to use third party library, namely portaudio in my
application. Unfortunately,
it is C API and has callback function in it. I have linking probplems again.
How do I solve this
callback problem?

Thank

Here is the error :

1>record.obj : error LNK2001: unresolved external symbol "public: static int
__cdecl RecordThread::recordCallback(void const *,void *,unsigned
long,struct PaStreamCallbackTimeInfo const *,unsigned long,void *)"
(?recordCallback@RecordThread@@SAHPBXPAXKPBUPaStreamCallbackTimeInfo@@K1@Z):

and here the header :

#include <QMutex>
#include <QSize>
#include <QThread>
#include <QWaitCondition>
#include "def.h"
#include "struct.h"
#include "c:\Users\portaudio\include\portaudio.h"
#define SAMPLE_RATE (44100)
#define FRAMES_PER_BUFFER (1024)
#define NUM_SECONDS (5)
#define NUM_CHANNELS (2)
/* #define DITHER_FLAG (paDitherOff) */
#define DITHER_FLAG (0) /**/

/* Select sample format. */
#if 1
#define PA_SAMPLE_TYPE paFloat32
typedef float SAMPLE;
#define SAMPLE_SILENCE (0.0f)
#define PRINTF_S_FORMAT "%.8f"
#elif 1
#define PA_SAMPLE_TYPE paInt16
typedef short SAMPLE;
#define SAMPLE_SILENCE (0)
#define PRINTF_S_FORMAT "%d"
#elif 0
#define PA_SAMPLE_TYPE paInt8
typedef char SAMPLE;
#define SAMPLE_SILENCE (0)
#define PRINTF_S_FORMAT "%d"
#else
#define PA_SAMPLE_TYPE paUInt8
typedef unsigned char SAMPLE;
#define SAMPLE_SILENCE (128)
#define PRINTF_S_FORMAT "%d"
#endif

typedef struct
{
    int frameIndex; /* Index into sample array. */
    int maxFrameIndex;
    SAMPLE *recordedSamples;
}
paTestData;

QT_BEGIN_NAMESPACE
class QImage;
QT_END_NAMESPACE
class RecordThread : public QThread
{
    Q_OBJECT

public:
    RecordThread(QObject *parent = 0);
    ~RecordThread();
    unsigned int uiBuffer[BUFFERSIZE];
    bool on_going_flag;
    void start_recording();
    void stop_recording();
static int recordCallback( const void *inputBuffer, void *outputBuffer,
                           unsigned long framesPerBuffer,
                           const PaStreamCallbackTimeInfo* timeInfo,
                           PaStreamCallbackFlags statusFlags,
                           void *userData );

signals:
   void record_signal(const QByteArray &record_QByteArray, int length);

public:

protected:
    void run();

private:
    REC_SOUND rec_sound;
    bool restart;
    bool abort;

    bool sound_init_flag;
    QMutex mutex;
    QWaitCondition condition;
    bool recording_flag;
};

and the class:
#include <QtGui>
#include "record.h"
#define OUTPUT_WAVE_FILE "Capture.wav"
#define SERVICE_UPDATE_PERIOD (20)

#define TEST_WAVE_FILE "stereo.wav"

RecordThread::RecordThread(QObject *parent)
    : QThread(parent)
{
    int i;
    restart = false;
    abort = false;
    sound_init_flag=false;
    for (i=0;i<MAX_REC_SOUND;++i)
    {
      rec_sound.status[i]=-1;
      rec_sound.buffer[i]=new char[BUFFERSIZE];
    }
    on_going_flag=false;

}
//! [0]

RecordThread::~RecordThread()
{
    int i;
    mutex.lock();
    abort = true;
    condition.wakeOne();
    mutex.unlock();
    for (i=0;i<MAX_REC_SOUND;++i)
      delete rec_sound.buffer[i];
    wait();
}

void RecordThread::start_recording()
{
     recording_flag=true;
    if (!isRunning()) {
        start(LowPriority);
    } else {
        restart = true;
        condition.wakeOne();
    }

}
void RecordThread::stop_recording()
{
     recording_flag=false;
    if (!isRunning()) {
        start(LowPriority);
    } else {
        restart = true;
        condition.wakeOne();
    }

}
static int recordCallback( const void *inputBuffer, void *outputBuffer,
                           unsigned long framesPerBuffer,
                           const PaStreamCallbackTimeInfo* timeInfo,
                           PaStreamCallbackFlags statusFlags,
                           void *userData )
{
    paTestData *data = (paTestData*)userData;
    const SAMPLE *rptr = (const SAMPLE*)inputBuffer;
    SAMPLE *wptr = &data->recordedSamples[data->frameIndex * NUM_CHANNELS];
    long framesToCalc;
    long i;
    int finished;
    unsigned long framesLeft = data->maxFrameIndex - data->frameIndex;

    (void) outputBuffer; /* Prevent unused variable warnings. */
    (void) timeInfo;
    (void) statusFlags;
    (void) userData;

    if( framesLeft < framesPerBuffer )
    {
        framesToCalc = framesLeft;
        finished = paComplete;
    }
    else
    {
        framesToCalc = framesPerBuffer;
        finished = paContinue;
    }

    if( inputBuffer == NULL )
    {
        for( i=0; i<framesToCalc; i++ )
        {
            *wptr++ = SAMPLE_SILENCE; /* left */
            if( NUM_CHANNELS == 2 ) *wptr++ = SAMPLE_SILENCE; /* right */
        }
    }
    else
    {
        for( i=0; i<framesToCalc; i++ )
        {
            *wptr++ = *rptr++; /* left */
            if( NUM_CHANNELS == 2 ) *wptr++ = *rptr++; /* right */
        }
    }
    data->frameIndex += framesToCalc;
    return finished;
}

void RecordThread::run()
{
    forever
    {
       PaStreamParameters inputParameters,
                           outputParameters;
       PaStream* stream;
       PaError err = paNoError;
       paTestData data;
       int i;
       int totalFrames;
       int numSamples;
       int numBytes;
       SAMPLE max, val;
       double average;
       if (!sound_init_flag)
       {
       data.maxFrameIndex = totalFrames = NUM_SECONDS * SAMPLE_RATE; /*
Record for a few seconds. */
       data.frameIndex = 0;
       numSamples = totalFrames * NUM_CHANNELS;
       numBytes = numSamples * sizeof(SAMPLE);
       data.recordedSamples = (SAMPLE *) malloc( numBytes ); /* From now on,
recordedSamples is initialised. */
       if( data.recordedSamples == NULL )
       {
           printf("Could not allocate record array.\n");
       // goto done;
       }
       for( i=0; i<numSamples; i++ ) data.recordedSamples[i] = 0;

       err = Pa_Initialize();
       if (err == paNoError )
       {
          inputParameters.device = Pa_GetDefaultInputDevice(); /* default
input device */
          inputParameters.channelCount = 2; /* stereo
input */
          inputParameters.sampleFormat = PA_SAMPLE_TYPE;
          inputParameters.suggestedLatency = Pa_GetDeviceInfo(
inputParameters.device )->defaultLowInputLatency;
          inputParameters.hostApiSpecificStreamInfo = NULL;

    /* Record some audio. -------------------------------------------- */
          err = Pa_OpenStream(
                 &stream,
                 &inputParameters,
                 NULL, /* &outputParameters, */
                 SAMPLE_RATE,
                 FRAMES_PER_BUFFER,
                 paClipOff, /* we won't output out of range samples so
don't bother clipping them */
                 recordCallback,//(void const *,void *,unsigned long,struct
PaStreamCallbackTimeInfo const *,unsigned long,void *),
                 &data );
          if( err != paNoError ) sound_init_flag=false;
       } else sound_init_flag=false;
    }
  }
}

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