auto-orient with MagickCore/Magick++

[umlaeute]

While investigating my own version of the famous "TGA is upside-down" problem, i noticed that the following command produces correctly-oriented TGA-images (i think this is mentioned in practically all "bug-reports" about the "wrong TGA orientation", so no real suprise here):

convert -auto-orient input.XXX output.tga

How would I do that in C/C++ code (using MagicCore resp. Magick++)?

My naive assumption was, that I could write something like this (the code is obviously using Magick++; i assume that the MagickCore code would be equivalent):

#include <Magick++.h>
int main(int argc, char**argv) {
  Magick::Image image;
  image.read(argv[1]);
  image.autoOrient();
  image.write(argv[2]);
  return 0;
}

Unfortunately this produces upside-down TGA images when called like so: ./test orig.png test.tga.

So my question is: how can I mimick the -auto-orient functionality in my C/C++ code?

(I would like to stay away from MagickWand if possible; mainly to keep dependencies down)