Esteemed Monks,

I wanted to experiment with calling OpenCV v4.1.2 C++-api functions from within Perl via Inline::CPP

I have encountered a couple of problems, the last of which is insurmountable to me.

The first problem is that OpenCV defines a seed(unsigned s) function in /usr/local/include/opencv4/opencv2/core.hpp which conflicts with Perl's seed macro. That can be overcome by adding #undef seed at the top of my CPP section (see https://github.com/Leont/libperl--/issues/5). Although it passes that, it's no good news at all.

The second problem is that OpenCV uses internally the namespace cv (e.g. /usr/local/include/opencv4/opencv2/core/cvdef.h) which conflicts with Perl's struct cv in perl5/CORE/sv.h.

Any ideas or is that the end of the road for my efforts?

CPAN module Cv has not been updated since 2013 and is based on a very outdated OpenCV C-api (it includes #include <opencv/cv.h>) which no longer exists in version 3 or 4 of OpenCV. Just mentioning that that's not an option ...

Here is a sample code

#!/usr/bin/perl

use strict;
use warnings;

use Inline CPP => DATA =>
 CCFLAGS => '-std=c++11',
 LIBS => '-L/usr/local/lib64 -lopencv_imgcodecs -lopencv_core',
 INC => '-I/usr/local/include/opencv4'
;

my $scrabble_image = 'IMAGES/scrabble_board1.jpg';

my $x = scrabbler($scrabble_image);

__END__
__CPP__
#undef seed
#include <iostream>
#include <stdexcept>
#include <stdlib.h>
#include <math.h>
#include <unordered_map>
#include <map>

#include <opencv2/core/types_c.h>
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/features2d/features2d.hpp>

int scrabbler(char *imname){
    cv::Mat myInputImage = cv::imread(imname);
    int W = myInputImage.cols;
    int H = myInputImage.rows;
    std::cout << "read image '" << imname << "': W=" << W << ", H=" <<
+ H << std::endl;
    return 1;
}

[download]

Many thanks, bliako

Update: added corrected cv::imread to sample code

In reply to Inline::CPP + OpenCV = problems by bliako

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