writing metadata

i ma working on writing metadata to a tiff image as xmp file.

I use the following code:
//Writing Metadata into image
	
         Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(filename.toStdString());
	assert(image.get()!=0);
	image->setExifData(exifData);
	image->writeMetadata();

but i am getting a error saying AutoPtr not a member og Exiv2::Image