If the search is successful (i.e. a card is found which matches the template), the contents of the card are (optionally) returned and the Card attribute is adjusted to identify the card found or, if required, the one following it. If the search is not successful, the function returns zero and the Card attribute is set to the "end-of-file".
A field specifier starts with a "%" character. This is followed by an optional single digit (0 to 9) specifying a field width. Finally, there is a single character which specifies the type of character to be matched, as follows:
If the field width is omitted, the field specifier matches one or more characters. If the field width is zero, it matches zero or more characters. Otherwise, it matches exactly the number of characters specified. In addition to this:
For example:
AST A Library for Handling World Coordinate Systems in Astronomy