astSetFitsCMastSetFitsCM - Store a comment card in a FitsChan

Description:
This function stores a comment card ( i.e. a card with no keyword name or equals sign) within a FitsChanFitsChan at the current card position. The new card can either over-write an existing card, or can be inserted as a new card into the FitsChan.
Synopsis:
void astSetFitsCM( AstFitsChan $*$this, const char $*$comment, int overwrite )
Parameters:
this
Pointer to the FitsChan.
comment
A pointer to a null terminated string holding the text of the comment card. If a NULL pointer or a blank string is supplied, then a totally blank card is produced.
overwrite
If non-zero, the new card over-writes the current card, and the current card is incremented to refer to the next card (see the "CardCard" attribute). If zero, the new card is inserted in front of the current card and the current card is left unchanged. In either case, if the current card on entry points to the "end-of-file", the new card is appended to the end of the list.
Notes:
  • If, on exit, there are no cards following the card written by this function, then the current card is left pointing at the "end-of-file".