Revision history [back]

Could anyone advise on the following error ?

Verbose terminal output

phung@UbuntuHW15:~/Documents/fpga_overlay/xillybus-eval-xl-virtex7-2.0b_DATE/verilog/vivado/xillydemo.srcs/sources_1/imports/taylor$ gcc -g host.c -o host `pkg-config --cflags --libs opencv`
phung@UbuntuHW15:~/Documents/fpga_overlay/xillybus-eval-xl-virtex7-2.0b_DATE/verilog/vivado/xillydemo.srcs/sources_1/imports/taylor$ ./host 
OpenCV Error: Bad argument (Unknown array type) in cvarrToMat, file /build/opencv-SviWsf/opencv-2.4.9.1+dfsg/modules/core/src/matrix.cpp, line 698
terminate called after throwing an instance of 'cv::Exception'
  what():  /build/opencv-SviWsf/opencv-2.4.9.1+dfsg/modules/core/src/matrix.cpp:698: error: (-5) Unknown array type in function cvarrToMat

Aborted (core dumped)
phung@UbuntuHW15:~/Documents/fpga_overlay/xillybus-eval-xl-virtex7-2.0b_DATE/verilog/vivado/xillydemo.srcs/sources_1/imports/taylor$ read() failed: Input/output error

host.c

#include <stdio.h>
#include <unistd.h>

#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdint.h>

#include "opencv2/core/core.hpp"
#include "opencv2/features2d/features2d.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/calib3d/calib3d.hpp"



#define N 512

struct packet{
  uint8_t r,g,b;
};


int main(int argc, char *argv[]) {

  int fdr, fdw, rc, donebytes;
  char *buf;
  pid_t pid;
  struct packet *tologic, *fromlogic;
  int i;
  float a, da;

  fdr = open("/dev/stdin", O_RDONLY);
  fdw = open("/dev/stdout", O_WRONLY);

  if ((fdr < 0) || (fdw < 0)) {
    perror("Failed to open Xillybus device file(s)");
    exit(1);
  }

  pid = fork();

  if (pid < 0) {
    perror("Failed to fork()");
    exit(1);
  }

  if (pid) {
    close(fdr);

        tologic = malloc(sizeof(struct packet) * N * N);  // lena.tiff is sized as 512*512*3
        if (!tologic) {
          fprintf(stderr, "Fa

iled to allocate memory\n");
      exit(1);
    }

    CvArr* src = cvLoadImageM("lena512color.tiff", CV_LOAD_IMAGE_COLOR); //load image

    CvArr *r, *g, *b;   //destination array

    // https://docs.opencv.org/2.4/modules/core/doc/operations_on_arrays.html#split

    cvSplit(src, r, g, b, (CvArr *)NULL); // split source into its respective [r, g, b] components
//Note: OpenCV uses BGR color order
//https://docs.opencv.org/2.4.13.6/modules/core/doc/old_basic_structures.html?highlight=cvarr#get-d

cvGet1D(b, tologic[i].b); // blue channel
cvGet1D(g, tologic[i].g); // green channel
cvGet1D(r, tologic[i].r); // red channel

    buf = (char *) tologic;
    donebytes = 0;

    while (donebytes < sizeof(struct packet) * N) {
      rc = write(fdw, buf + donebytes, sizeof(struct packet) * N - donebytes);

      if ((rc < 0) && (errno == EINTR))
        continue;

      if (rc <= 0) {
        perror("write() failed");
        exit(1);
      }

      donebytes += rc;
    }

    sleep(1); // Let debug output drain (if used)

    close(fdw);

    return 0;
  } 

  else {
    close(fdw);

    fromlogic = malloc(sizeof(struct packet) * N);
    if (!fromlogic) {
      fprintf(stderr, "Failed to allocate memory\n");
      exit(1);
    }

    buf = (char *) fromlogic;
    donebytes = 0;

    while (donebytes < sizeof(struct packet) * N) {
      rc = read(fdr, buf + donebytes, sizeof(struct packet) * N - donebytes);

      if ((rc < 0) && (errno == EINTR))
    continue;

      if (rc < 0) {
    perror("read() failed");
    exit(1);
      }

      if (rc == 0) {
    fprintf(stderr, "Reached read EOF!? Should never happen.\n");
    exit(0);
      }

      donebytes += rc;
    }

   // for (i=0; i<N; i++)
      printf("R:%d G:%d B:%d \n", fromlogic[0].r, fromlogic[0].g, fromlogic[0].b);
      printf("R:%d G:%d B:%d \n", fromlogic[68499].r, fromlogic[68499].g, fromlogic[68499].b);
    sleep(1); // Let debug output drain (if used)

    close(fdr);
    return 0;
  }
}