Exiv2

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

// xmpsample.cpp, $Rev: 2286 $

// Sample/test for high level XMP classes. See also addmoddel.cpp

#include <exiv2/exiv2.hpp>

#include <string>

#include <iostream>

#include <iomanip>

#include <cassert>

#include <cmath>

bool isEqual(float a, float b)

{

    double d = std::fabs(a - b);

    return d < 0.00001;

}

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

try 

{

  if (argc != 2) 

  {

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

    return 1;

  }

  std::string testFile = argv[1];

  //Open File and write some XMP

  Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(testFile);

  assert(image.get() != 0);

  Exiv2::XmpData xmpDataW;

  Exiv2::XmpProperties::registerNs("R&S/", "RS");

  xmpDataW["Xmp.RS.SerialNumber"] = "12345678";

  xmpDataW["Xmp.RS.SoftwareVersion"] = "9.9.9.9";

  image->setXmpData(xmpDataW);

  image->writeMetadata();

  image.release();

  Exiv2::Image::AutoPtr imageOpenSameFileAgain = Exiv2::ImageFactory::open(testFile);

  assert(imageOpenSameFileAgain.get() != 0);

  imageOpenSameFileAgain->readMetadata();

  Exiv2::XmpData &xmpDataR = imageOpenSameFileAgain->xmpData();

  if (xmpDataR.empty()) 

  {

    std::string error(argv[1]);

    error += ": No XMP data found in the file";

    throw Exiv2::Error(1, error);

  }

  else

  {

    Exiv2::XmpData::const_iterator pos = xmpDataR.findKey(Exiv2::XmpKey("Xmp.RS.SoftwareVersion"));

    if (pos == xmpDataR.end()) 

    {

      std::string error(argv[1]);

      error += ": SoftwareVersion not found in XMP data of the file";

      throw Exiv2::Error(1, error);

    }

    Exiv2::Value::AutoPtr v = pos->getValue();

    assert(v->ok());

    std::string sXMPValue = v->toString();

    std::cout << sXMPValue << "\n";

  }

  return 0;

}

catch (Exiv2::AnyError& e) 

{

    std::cout << "Caught Exiv2 exception '" << e << "'\n";

    return -1;

}