Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc.

NAME

  fpos

SYNOPSIS

  #include <rw/iotraits>
  template<class stateT = mbstate_t>
  class fpos

DESCRIPTION

  The template class fpos<stateT> is used by the iostream classes to maintain
  positioning information. It maintains three kinds of information:  the
  absolute position, the conversion state and the validity of the stored
  position. Streams instantiated on tiny characters use streampos as their
  positioning type, whereas streams instantiated on wide characters use
  wstreampos, but both are defined as fpos<mbstate_t>.

INTERFACE

  template <class stateT = mbstate_t>
  class fpos {

  public:

   typedef stateT  state_type;

   fpos(long off = 0);
   fpos(state_type);

   state_type   state(state_type);
   state_type   state () const;

  };

TYPES

  state_type
     The type state_type holds the conversion state, and is compatible with
     the function locale::codecvt(). By default it is defined as mbstate_t.

PUBLIC CONSTRUCTORS

  fpos(long off =0);
     Constructs an fpos object, initializing its position with off and its
     conversion state with the default stateT constructor. This function is
     not described in the C++ standard.

  fpos(state_type st);
     Construct an fpos object, initializing its conversion state with st, its
     position with the start position, and its status to good.

PUBLIC MEMBER FUNCTIONS

  state_type
  state() const;
     Returns the conversion state stored in the fpos object.

  state_type
  state(state_type st);
     Store st as the new conversion state in the fpos object and return its
     previous value.

VALID OPERATIONS

  In the following,

  •       P refers to type fpos<stateT>

  •       p and q refer to an value of type fpos<stateT>

  •       O refers to the offset type ( streamoff, wstreamoff, long _)

  •       o refers to a value of the offset type

  •       i refers to a value of type int

  Valid operations:

  P p( i );    Constructs from int.

  P p = i;   Assigns from int.

  P( o )   Converts from offset.

  O( p )   Converts to offset.

  p == q   Tests for equality.

  p != q   Tests for inequality.

  q = p + o   Adds offset.

  p += o   Adds offset.

  q = p -o   Subtracts offset.

  q -= o   Subtracts offset.

  o = p - q   Returns offset.

SEE ALSO

  iosfwd(3C++std), char_traits(3C++std)

  Working Paper for Draft Proposed International Standard for Information
  Systems--Programming Language C++, Section 27.4.

  Amendment 1 to the C Standard.

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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