c++ - audio recording and real-time playing in windows using waveIn and waveOut -

i want record microphone audio input and, small time delay, play recorded sound immediately. done continuously using queue of buffers.

i got code running point continuously plays microphone audio input, there short still noticeable repeated pauses throughout whole audio output using waveout. causing these annoying pauses? , how remove them?

another question is, i'm not using thing mutex, i'm relying on fact wavein , waveout have same sampling rate , same amount of data, waveout follows wavein , wavein not write buffer being played. problem?

here's code, should compile , run. made code run, , it's far being written. comment on improving code highly welcome.

    #include "stdafx.h"     #include <windows.h>     #pragma comment(lib, "winmm.lib")     #include <iostream>     #include <fstream>     #include <sstream>      using namespace std;     handle hevent_bufferready;     handle hevent_finishedplaying;     #define samplerate 44100     #define nsec  1      int _ibuf;     int _iplaying;     unsigned long result;       hwavein hwavein;     hwaveout hwaveout;     waveformatex pformat;      enum { num_buf = 3 };     wavehdr _header [num_buf];      dword winapi recordingwaitingthread(lpvoid ivalue)     {         while(1)         {         waitforsingleobject(hevent_bufferready,infinite);           result = waveinunprepareheader (hwavein, &_header[_ibuf], sizeof (wavehdr));         _iplaying = _ibuf;         result = waveoutprepareheader(hwaveout, &_header[_ibuf], sizeof(wavehdr));         result = waveoutwrite(hwaveout, &_header[_ibuf], sizeof(wavehdr));   // play audio         ++_ibuf;         if (_ibuf == num_buf)   _ibuf = 0;         result = waveinprepareheader(hwavein, & _header[_ibuf], sizeof(wavehdr));         result = waveinaddbuffer (hwavein, & _header[_ibuf], sizeof (wavehdr));          }         return 0;     }      dword winapi playingwaitingthread(lpvoid ivalue)     {         while(1){             waitforsingleobject(hevent_finishedplaying,infinite);             waveoutunprepareheader(hwaveout, &_header[_iplaying], sizeof(wavehdr));         }     }      static void callback waveoutproc(hwaveout hwaveout, uint umsg, dword dwinstance, dword dwparam1,dword dwparam2 )     {     if(umsg != wom_done)     return;     setevent(hevent_finishedplaying);     }       void callback mywaveinproc(hwavein hwi, uint umsg, dword dwinstance, dword dwparam1, dword dwparam2)     {     if(umsg != wim_data)     return;     setevent(hevent_bufferready);     }      int main(int argc, _tchar* argv[])     {          hevent_bufferready=createevent(null,false, false, null);         hevent_finishedplaying = createevent(null,false, false, null);           pformat.wformattag = wave_format_pcm; // simple, uncompressed format         pformat.nchannels = 1; // 1=mono, 2=stereo         pformat.nsamplespersec = samplerate;          pformat.wbitspersample = 16; // 16 high quality, 8 telephone-grade         pformat.nblockalign = pformat.nchannels*pformat.wbitspersample/8;          pformat.navgbytespersec = (pformat.nsamplespersec)*(pformat.nchannels)*(pformat.wbitspersample)/8;          pformat.cbsize=0;           short int  *_pbuf;         size_t bpbuff =4000;//= (pformat.nsamplespersec) * (pformat.nchannels) * (pformat.wbitspersample)/8;         _pbuf = new short int [bpbuff * num_buf];          result = waveinopen(&hwavein, wave_mapper,&pformat, (dword)mywaveinproc, 0l, callback_function);         result = waveoutopen(&hwaveout, wave_mapper, &pformat, (dword_ptr)waveoutproc, 0, callback_function);         // initialize headers in queue         ( int = 0; < num_buf; i++ )         {             _header[i].lpdata = (lpstr)&_pbuf [i * bpbuff];             _header[i].dwbufferlength = bpbuff*sizeof(*_pbuf);             _header[i].dwflags = 0l;             _header[i].dwloops = 0l;         }          dword mythreadid;         dword mythreadidplay;         handle hthread;         handle hthreadplay;         hthread = createthread(null, 0, recordingwaitingthread,null,0,&mythreadid);         hthreadplay = createthread(null, 0, playingwaitingthread,null,0,&mythreadidplay);          _ibuf = 0;          waveinprepareheader(hwavein, & _header[_ibuf], sizeof(wavehdr));         waveinaddbuffer (hwavein, & _header[_ibuf], sizeof (wavehdr));          waveinstart(hwavein);          getchar();         waveinclose(hwavein);         waveoutclose(hwaveout);         closehandle(hthread);         closehandle(hthreadplay);          closehandle(hevent_bufferready);         closehandle(hevent_finishedplaying);          return 0;     }