codecvt::do_length

A virtual function that determines how many Bytes from a given sequence of external Bytes produce not more than a given number of internal CharTypes and returns that number of Bytes.

virtual int do_length(
    const StateType& _State,
    const Byte* _First1, 
    const Byte* _Last1,
    size_t _Len2
) const;

Parameters

• _State
  The conversion state that is maintained between calls to the member function.

• _First1
  Pointer to the beginning of the external sequence.

• _Last1
  Pointer to the end of the external sequence.

• _Len2
  The maximum number of Bytes that can be returned by the member function.

Return Value

An integer that represents a count of the maximum number of conversions, not greater than _Len2, defined by the external source sequence at [_First1, _Last1).

Remarks

The protected virtual member function effectively calls do_in(_State, _First1, _Last1, _Next1, _Buf, _Buf + _Len2, _Next2) for _State (a copy of state), some buffer _Buf, and pointers _Next1and _Next2.

It then returns _Next2 – buf. Thus, it counts the maximum number of conversions, not greater than _Len2, defined by the source sequence at [_First1, _Last1).

The template version always returns the lesser of _Last1 – _First1 and _Len2.

Example

See the example for length, which calls do_length.

Requirements

Header: <locale>

Namespace: std

See Also

Reference

codecvt Class