include <iostream>

include <cv.h>

include <highgui.h>

#include <iostream>
#include <cv.h>
#include <highgui.h>
using namespace std;
 
include <sys types.h="">
 
include <sys ipc.h="">
 
include <sys shm.h="">
 
include <stdio.h>
 
include "2cam.h"
 
std;

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>

#include "2cam.h"

int sizeofmat(CvMat *mat) {
    return mat->rows * mat->step;
}
 
}

int main() {
    int shmid;
    key_t key = 5678;
 
5678;

    uchar *vdisp;
 CvMat *s = cvCreateMat(240, 320, CV_8U);
 CvMat *tmp = cvCreateMat(240, 320, CV_8U);
 const size_t vdispsize = sizeofmat(s);
 CvMat stub;
 CvSize imageSize = cvSize(320, 240);

 IplImage *color = cvCreateImage(imageSize, 8, 3);
 IplImage *gray = cvCreateImage(imageSize, 8, 1);

 /* Create the segment */
 if ((shmid = shmget(key, vdispsize, IPC_CREAT | 0666)) < 0) {
     perror("shmget");
     exit(1);
}

    }

    /* Attach the segment to our data space */
 if ((vdisp = (uchar *) shmat(shmid, NULL, 0)) == (uchar *) -1) {
     perror("shmat");
     exit(1);
}

    }

    s->data.ptr = vdisp;

 /* Create camera */
 Camera c("/dev/video0", 320, 240, 30);

 while (1) {
     /* Get one frame */
     c.Update();
     c.toIplImage(color);

     /* Convert color frame to grayscale */
     cvCvtColor(color, gray, CV_BGR2GRAY);

     /* Get matrix from the gray frame and write the matrix in shared memory*/
     tmp = cvGetMat(gray, &stub, 0, 0);

     for (int row = 0; row < tmp->rows; row++) {
         const uchar* ptr = (const uchar*) (tmp->data.ptr + row * tmp->step);
         memcpy((uchar*)(s->data.ptr + row * s->step), ptr, tmp->step);
    }

    }

        /* Show frame */
     cvNamedWindow("result", CV_WINDOW_AUTOSIZE);
     cvShowImage("result", s);

     /* Wait for escape key */
     if ((cvWaitKey(10) & 255) == 27)
         break;
}

    }

    /* free memory */
 cvDestroyWindow("result");
 cvReleaseImage(&color);
 cvReleaseImage(&gray);

 return 0;
}
 
} 
Client code to retrieve from SHM
 
include <iostream>
 
include <cv.h>
 
include <highgui.h>
 
#include <iostream>
#include <cv.h>
#include <highgui.h>
using namespace std;
 
include <sys types.h="">
 
include <sys ipc.h="">
 
include <sys shm.h="">
 
include <stdio.h>
 
std;

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>

int sizeofmat(CvMat *mat) {
    return mat->rows * mat->step;
}
 
}

int main() {
    int shmid;
    key_t key = 5678;
 
5678;

    uchar *vdisp;
 CvMat *s = cvCreateMat(240, 320, CV_8U);
 const size_t vdispsize = sizeofmat(s);

 /* Locate the segment */
 if ((shmid = shmget(key, vdispsize, 0666)) < 0) {
     perror("shmget");
     exit(1);
}

    }

    /* Now we attach the segment to our data space */
 if ((vdisp = (uchar *)shmat(shmid, NULL, 0)) == (uchar *) -1) {
     perror("shmat");
     exit(1);
}

    }

    s->data.ptr = vdisp;

 cvNamedWindow("result", CV_WINDOW_AUTOSIZE);
 cvShowImage("result", s);

 cvWaitKey(10000);

 cvDestroyWindow("result");

 return 0;
}
 
} 
This code is working for grayscale and size of 320X240. Please help me to do the same for 3 channel image of 640X480.
 
Thanks and regards,
Prabhakar M