The text of any warning will be stored within the FitsChan in the form of one or more new header cards with keyword ASTWARN. If required, applications can check the FitsChan for ASTWARN cards (using astFindFits) after the call to astRead or astWrite has been performed, and report the text of any such cards to the user. ASTWARN cards will be propagated to any output header unless they are deleted from the FitsChan using astDelFits.
AST A Library for Handling World Coordinate Systems in Astronomy