Exiv2

#include <exiv2/exiv2.hpp>

#include <iostream>

#include <cassert>

#include <opencv2/highgui/highgui.hpp>

#include <opencv2/imgproc/imgproc.hpp> 

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

try {

    if (argc != 2) {

        std::cout << "Usage: " << argv[0] << " file\n";

        return 1;

    }

    cv::Mat cvImage = cv::imread(argv[1], CV_LOAD_IMAGE_COLOR);

    // Create a new buffer for jpeg encoded image.

    std::vector<uchar> cvbuff;

    cv::imencode(".jpg",cvImage,cvbuff, std::vector<int>());

    Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(&cvbuff[0], cvbuff.size());

    image->readMetadata();

    Exiv2::ExifData &exifData = image->exifData();

    exifData["Exif.Image.Model"] = "A long model name to make the Exif metadata grow";

    image->writeMetadata();

    // 1. Writing to disk

    // Create a new file for writing.

    FILE * file1 = ::fopen("mm2.jpg", "w");

    ::fclose(file1);

    // Now open using FileIo for writing.

    Exiv2::FileIo file("mm2.jpg");

    file.open();

    file.write(image->io());

    // 2. Writing to disk

    // This works but does not write metatags.

    // FILE * file = ::fopen("mm.jpg", "w"); 

    //::fwrite(&cvbuff[0], image->io().size(), 1, file); 

    //::fclose(file); 

    return 0;

}

catch (Exiv2::Error& e) {

    std::cout << "Caught Exiv2 exception '" << e.what() << "'\n";

    return -1;

}