opencv-webcam stream cannot be received by another process via named fifo

Question

Hi i am trying to simulate a client-server program.Both are independent processes.The client listens for image data(mat.data) written on a named fifo by the server (which reads image frames from a webcam and writes them one by one on the namedfifo) My server and client sides work perfectly, if I create a simple mat object on the client side ,write it on the fifo,read it on the server and recreate it on the server side.However, when I try to write a continuous stream of frames from webcam, the server gives core-dump, segmentation fault.

The server side code is shown below.

     #include <stdio.h>
     #include <opencv2/opencv.hpp>
     #include <opencv2/core/core.hpp>
     #include <iostream>
     #include <stdlib.h>
     #include <sys/types.h>
     #include <sys/stat.h>
     #include <fcntl.h>
     #include <unistd.h>
     int main(int, char**)
     {
      VideoCapture cap(0); // open the default camera
      if(!cap.isOpened())  // check if we succeeded
       return -1;

      int check;
      int fd;
      int totalbytes;
      int buflen;

      fd = open("/home/vidfifo",O_WRONLY|O_NONBLOCK);

      for(;;)
      {
        Mat frame;
        cap >> frame; // get a new frame from camera

        int  totalbytes = frame.total()*frame.elemSize();
        int buflen = frame.cols*3;

        check = writefifo(frame.data,totalbytes,buflen,fd);

        if (check == 1)
        {
          cout<<"write successful"<<endl;
          imshow("frames1", frame);
          if(waitKey(30) >= 0) break;
        }
        else
        {
          break;
        }
    }
       close(fd);
       return 0;
    }

the writefifo function is as follows

    int writefifo(uchar *framepointer,int totalbytes,int buflen,int fd)
    {
      uchar* buf;
      buf = framepointer;
      int num = totalbytes/buflen;
      for(int i = 1;i<=num;i++)
      {
        write(fd,buf,buflen);
        buf = buf + buflen;
      }
      return 1;
     }

the client side is

    #include <stdio.h>
    #include <opencv2/opencv.hpp>
    #include <opencv2/core/core.hpp>
    #include <iostream>
    #include <stdlib.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <unistd.h>
    int main( int argc, char** argv )
    {
      //I found these by running the server program beforehand          
      int rows = 480;
      int cols = 640;
      int nchan = 3;
      int totalbytes = 921600;//rows*cols*nchan
      int buflen = 1920;//cols*nchan

      while(1)
      {
         Mat img(rows,cols,CV_8UC3);
         uchar buf[buflen];
         uchar datarray[totalbytes];

         int fd1 = open("/home/vidfifo",O_RDONLY);
         int j;
         int k = 0;
         int num = totalbytes/buflen;//=num of rows

         for(int i = 1;i<=num;i++)
         {
           read(fd1,buf,buflen);
           for ( j = 0 ; j<= (buflen-1);j++ ) //originally wrote this as j<= (buflen-1+k)--see update1 at the end of post
           {
              datarray[j+k] = buf[j];

           }
              k = k+buflen;
           }

           img.data = datarray;
           imshow("framesrec", img);
           if(waitKey(30) >= 0) break;
     }
            return 0;
     }

I know there's something wrong with a pointer in the server program.But I can't figure out what. Please tell me if there is some pointer related issue or something else in the code that does not allow the client to receive a continuous stream of frames. Thanks.

update1 after posting this question, I realized I should have written the limit of the read loop( in server) as j<=(buflen -1) instead of j<=(buflen-1+k).This removed the segmentation error, but all I get is a corrupted frozen frame instead of a continuous stream and the window stops responding after some time.So, now my question is How do I get a continuous stream?

update2 after putting the close system call outside loop in the server code, i now get a continuous stream but it is blurred and frames appear squashed.Still not a perfect stream.