Opencv FileStorage operation - failed to open:

Question

I have been struggling for a while by the failure to open file using FileStorage: It is part of the code from: \opencv\sources\samples\cpp\tutorial_code\calib3d\camera_calibration\camera_calibration.cpp:

FileStorage fs(inputSettingsFile, FileStorage::READ); // Read the settings
if (!fs.isOpened())
{
    cout << "Could not open the configuration file: \"" << inputSettingsFile << "\"" << endl;
    return -1;
}

It always failed. Tried absolute path also, still fails. Environment: Opencv version: 2.4.8, windows 7 (32-bit) and Visual Studio 2010. (Actually, tried 2.4.2 and VS2008, same problem) Anything I am missing?

To verify permission, added regular cpp file read before FileStorage. the regular cpp file read works fine:

int main()
{
    ////Use two ways to open and read the file "in_VID5.xml"

    string inputSettingsFile = "in_VID5.xml";
    //// Method 1: cpp read file - ok
    ifstream myfile(inputSettingsFile);
    string line;
    if(myfile.is_open())
    {
        while (getline(myfile, line))
        {
            ////It does come here
            cout << line <<'\n';
        }
        myfile.close();
    }

    Sleep(1000);
    ////Method 2: opencv read file - fails
    FileStorage fs(inputSettingsFile, FileStorage::READ); // Read the settings
    if (!fs.isOpened())
   {
        ////It fails
        cout << "Could not open the configuration file: \"" << inputSettingsFile << "\"" << endl;
        return -1;
    }
    return 0;
}

Is the file path ".xml", ".yml" or ".yaml"? Please select the edit button on your post and respond to us. I take it that you don't have enough reputation to comment yet. — David G
Thanks for all the replies. I did check the permission. Extension is ".xml" — Cloud Guy
To verify the permission. A few lines of regular cpp file read is added before that and it works fine. But once it comes to that FileStorage constructor and then check if it is opened, it fails — Cloud Guy

Mónica Mónica · Accepted Answer · 2016-08-27T06:59:11

I had the same problem until I realized that the constructor doesn't work with the READ flag. So what I do is: - I use the constructor with the falg APPEND. If I use WRITE the contents of the file is deleted. - Then I open with the READ flag and work with the content.

Opencv FileStorage operation - failed to open:

3 Answers