Yes, correct. I use a textfile in the /tmp to keep a counter. Doing a platesolve for every fits-image captured would take too much time. It's only necessary every 10th or 20th file orso. There is drift, but not heavy. Because the script is launched after every exposure I have to keep the counter somewhere externally.

So the script just reads the counter from the textfile, and when the counter is 10 or 20 orso, it has to do the platesolve on the last image.
Now question is: how do I retrieve that filename? I haven't found it in the documentation. After that, I just pass it to the method.
startSolving (const QString &filename, bool isGenerated=true)