在Windows OS中，如何将数据从OpenCV或C ++线程函数返回到主线程？

Question

I am not much familiar with openCV or C++ threading.

The main problem is I am passing some data to the thread function, it does some processing and after that IT NEEDS TO RESEND THE PROCESSED DATA.

In Win 32 or VC++ this return data we can post/postthread through a message to the main thread in case of UI Threads, but in case of worker threads there is no facility to return the data.

What about openCV or C++ threading case how to send the return data to the main thread? Can you please give me idea how to do this.

The code I am using is as like below

// .h file
#define MAX_THREADS 3
#include "windows.h"

typedef struct MyData {
              unsigned char* colorPixelData;
              uint32* punTIFFImageData;
              int ii;
              int jj;
              int hh;
              int ww;
              int nWidth;
              int kk;
       } MYDATA, *PMYDATA;

void MyThreadFunction(void *arg);

and

//   .cpp file, Main thread
PMYDATA pDataArray[MAX_THREADS];
PMYDATA pReturnedDataArray[MAX_THREADS];
HANDLE  hThreadArray[MAX_THREADS];

//some code
hThreadArray[count] = CreateThread( 
                                    NULL,                   
                                    0,                      
                                    (LPTHREAD_START_ROUTINE)MyThreadFunction,       
                                    (void *)&pDataArray[count],  // argument to thread function 
                                    0,                      
                                    NULL);   

WaitForMultipleObjects(MAX_THREADS, hThreadArray, TRUE, INFINITE);


//called thread function
void MyThreadFunction(void *arg) 
{ 
     //NEED TO RETURN DATA FROM HERE TO MAIN THREAD  pReturnedDataArray
}

Answer 1

Use global variables instead so other threads can read/write on them.

By doing this you don't need to worry about a thread "returning something".

Answer 2

You can use std::thread that is supported in C++11 standard. Then you can pass your pDataArray[count] and as many other variables as you want so you don't have to return anything to get your output. You can get more informations about this class here: http://www.cplusplus.com/reference/thread/thread/