Exiv2

// ***************************************************************** -*- C++ -*-

// memIo.cpp, $Rev$

// Sample program to print the Exif metadata of an image

#include <exiv2/exiv2.hpp>

#include <iostream>

#include <cassert>

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

try {

    if (argc != 2) {

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

        return 1;

    }

    Exiv2::DataBuf buf = Exiv2::readFile(argv[1]);

    Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(buf.pData_, buf.size_);

    image->readMetadata();

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

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

    image->writeMetadata();

    Exiv2::FileIo file(argv[1]);

    file.open();

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

    return 0;

}

catch (Exiv2::Error& e) {

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

    return -1;

}