codecvt::length

int length ( stateT& state, const externT* from, const externT* from_end, size_t max ) const;

Return length of translated sequence

Parameters

state

State object to keep track of the state of a multibyte character conversion. Typically, this is an object of type mbstate_t.
stateT is the state type (i.e., the third template parameter of codecvt).

from, from_end

Pointer to the initial and final characters of the source sequence. The range used is [from,from_end), which contains all the characters between from and from_end, including the character pointed by from but not the character pointed by from_end.
externT is the external character type (i.e., the second template parameter of codecvt).

max

Maximum length of the translated sequence (in terms of internal characters).
size_t is an integral type.

Return value

Example

// codecvt::length example
#include <iostream>
#include <locale>
using namespace std;
int main ()
{
  locale loc;
  mbstate_t mystate;
  char origin[] = "abcdefghijklmnopqrstuvwxyz";
  const char * pc;
  wchar_t * pwc;
  const codecvt<wchar_t,char,mbstate_t>& myfacet = 
    use_facet<codecvt<wchar_t,char,mbstate_t> >(loc);
  // calculate length for 10 wchar_t's:
  int length = myfacet.length (mystate, origin, origin+sizeof(origin), 10);
  wchar_t * dest = new wchar_t[length+1];
  myfacet.in (mystate, origin, origin+sizeof(origin), pc, dest, dest+length, pwc);
  dest[length]=0;  // Terminating null-character
  cout << "A string of 10 wchar_t elements: ";
  wcout << dest << endl;
  return 0;
}

A string of 10 wchar_t elements: abcdefghij

See also