From simon.urbanek at r-project.org  Thu Nov  8 21:26:54 2012
From: simon.urbanek at r-project.org (Simon Urbanek)
Date: Thu, 8 Nov 2012 15:26:54 -0500
Subject: [Rd] unable to load shared object - opencv
In-Reply-To: <1352405973652-4648958.post@n4.nabble.com>
References: <1352405973652-4648958.post@n4.nabble.com>
Message-ID: <41EEA755-C100-4F04-9E02-92CF7F1294B8@r-project.org>


On Nov 8, 2012, at 3:19 PM, niandra wrote:

> Hi all
> 
> i'm trying to use the opencv's function into R.
> 
> i wrote a simple script, just for try to understand how use c++ in R, it
> loads an image and write it with a different name (i know it ), and then
> write "Hello, World". The file is names prova2.cpp (is the first time i try
> to use c++ )
> 
> #include <stdio.h>
> #include <opencv/cv.h>
> #include <opencv2/core/core.hpp>
> #include <opencv2/highgui/highgui.hpp>
> #include <opencv/highgui.h>
> #include <opencv/cv.h> 
> #include <R.h>
> #include <Rinternals.h>
> 
> extern "C" SEXP provaR(void) {
> cv::Mat gravit;
> gravit=cv::imread("imm.jpg");
> cv::imwrite("imm_dop.jpg",gravit);
> Rprintf("Hello, World!nn");
> return R_NilValue;
> }
> 
> Now in the terminal  i type R CMD SHLIB  prova2.cpp to create the file
> prova2.so and this happen without error.
> 
> In R i type dyn.load("prova2.so") and get this error:
> 
> Errore in dyn.load("prova2.so") : 
>  unable to load shared object
> '/Users/niandra/Desktop/statistico/r/builtpack/ProvaScript/prova2.so':
> 
> dlopen(/Users/niandra/Desktop/statistico/r/builtpack/ProvaScript/prova2.so,
> 6): Symbol not found: __ZN2cv11_InputArrayC1ERKNS_3MatE
>  Referenced from:
> /Users/niandra/Desktop/statistico/r/builtpack/ProvaScript/prova2.so
>  Expected in: flat namespace
> in /Users/niandra/Desktop/statistico/r/builtpack/ProvaScript/prova2.so
> 
> I understand that the problem is because i should tell R where to find the
> opencv library, but i really don't know how do it.
> 

add the necessary -l flags (see your configuration or pkgconfig) to R CMD SHLIB

Cheers,
S


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[Rd] unable to load shared object - opencv
Simon Urbanek