mk's profile - activity

I found that arithm_op was trying to access one InputArray that was a noArray() and, since the noArray function returns a static object, it may not be initialized.

My workaround was to change the definition of _none in modules/core/src/matrix.cpp:

//static _OutputArray _none;
static _OutputArray noneOutputArray()
{
    static _OutputArray none;
    return &none;
}
#define _none *noneOutputArray()

The define was used to avoid interferences with other code that may be using the _none object. (And to avoid the need to change that code)

I don't know if this can/will affect the behavior of other parts of OpenCV.

boaz001 I found that arithm_op was trying to access one InputArray that was a noArray() . And since the noArray function returns a static object, it may not be initialized. My workaround was to change the definition of _none in modules/core/src/matrix.cpp:

//static _OutputArray _none;
static _OutputArray noneOutputArray()
{
    static _OutputArray none;
    return &none;
}
#define _none *noneOutputArray()

The define was used to avoid interferences with other code that may be using the _none object. (And to avoid the need to change that code)

I am writing this in the comment because I cannot answer my own question yet. (only tomorrow)

Sure! The output is here: http://pastebin.com/FzJZBhJZ I also included a backtrace from gdb.

@boaz001 I already tried with the fix proposed for this issue, but it does not solve. I also added some debug msgs in the opencv code, and my program is not breaking inside the functions changed in the pull request: https://github.com/Itseez/opencv/pull/2558

I use some opencv functions in one lib that I build as a shared object (libfoo.so)
In order to have only one .so file loaded in runtime, I use opencv as a static lib (libopencv_*.a) linked in libfoo.so.

Inside libfoo.so I have one static object from a class (Bar), and in the constructor I do some simple cv::Mat operations like:

Bar::Bar(){
barMat = cv::Mat::zeros(...);
barMat += 1;
}
...
static Bar b;

The problem is that I always get a segfault when it reaches the += (or any other arithmetic operation with Mat).

The following is the smallest example I came up with to reproduce the fault:

#include <opencv2/opencv.hpp>
class Bug {
public:
Bug() {
cv::Mat M = cv::Mat::zeros(3,3,CV_8U);
M += 10;
}
};
static Bug b;
int main(int argc, char** argv){}


Compile with

$ g++ bug.cpp `pkg-config --cflags --libs opencv`

And run

$ ./a.out
Segmentation fault (core dumped)

I already checked another question that seems to be related, but none of the proposed fixes solve my case: http://answers.opencv.org/question/4072/initializing-static-cvmat-with-cvmatzeros-causes/ https://github.com/Itseez/opencv/pull/2558

I compiled OpenCV from 2.4.9 tar.

Can anyone help?