Miscellaneous `istream' utilities
---------------------------------

   Use these methods for housekeeping on `istream' objects:

 - Method: int istream::gcount ()
     Report how many characters were read from this `istream' in the
     last unformatted input operation.

 - Method: int istream::ipfx (int KEEPWHITE)
     Ensure that the `istream' object is ready for reading; check for
     errors and end of file and flush any tied stream.  `ipfx' skips
     whitespace if you specify `0' as the KEEPWHITE argument, *and*
     `ios::skipws' is set for this stream.

     To avoid skipping whitespace (regardless of the `skipws' setting on
     the stream), use `1' as the argument.

     Call `istream::ipfx' to simplify writing your own methods for
     reading `istream' objects.

 - Method: void istream::isfx ()
     A placeholder for compliance with the draft ANSI standard; this
     method does nothing whatever.

     If you wish to write portable standard-conforming code on `istream'
     objects, call `isfx' after any operation that reads from an
     `istream'; if `istream::ipfx' has any special effects that must be
     cancelled when done, `istream::isfx' will cancel them.

 - Method: istream& istream::ignore ([int N] [, int DELIM])
     Discard some number of characters pending input.  The first
     optional argument N specifies how many characters to skip.  The
     second optional argument DELIM specifies a "boundary" character:
     `ignore' returns immediately if this character appears in the
     input.

     By default, DELIM is `EOF'; that is, if you do not specify a
     second argument, only the count N restricts how much to ignore
     (while input is still available).

     If you do not specify how many characters to ignore, `ignore'
     returns after discarding only one character.

 - Method: istream& istream::putback (char CH)
     Attempts to back up one character, replacing the character
     backed-up over by CH.  Returns `EOF' if this is not allowed.
     Putting back the most recently read character is always allowed.
     (This method corresponds to the C function `ungetc'.)

 - Method: istream& istream::unget ()
     Attempt to back up one character.