codecvt::in (Standard C++ Library)

codecvt::in

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Standard C++ Library Reference

codecvt::in

Converts an external representation of a sequence of Bytes to an internal representation of a sequence of CharTypes.

result in(
   StateType& _State,
   const Byte* _First1, 
   const Byte* _Last1, 
   const Byte*& _Next1,
   CharType* _First2,
   CharType* _Last2,
   CharType*& _Next2,
);

Parameters

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

_First1: Pointer to the beginning of the sequence to be converted.

_Last1: Pointer to the end of the sequence to be converted.

_Next1: Pointer beyond the end of the converted sequence to the first unconverted character.

_First2: Pointer to the beginning of the converted sequence.

_Last2: Pointer to the end of the converted sequence.

_Next2: Pointer to the CharType that comes after the last converted Chartype to the first unaltered character in the destination sequence.

Return Value

A return that indicates the success, partial success or failure of the operation. The function returns:

codecvt_base::error if the source sequence is ill formed.
codecvt_base::noconv if the function performs no conversion.
codecvt_base::ok if the conversion succeeds.
codecvt_base::partial if the source is insufficient or if the destination is not large enough for the conversion to succeed.

Remarks

_State must represent the initial conversion state at the beginning of a new source sequence. The function alters its stored value, as needed, to reflect the current state of a successful conversion. After a partial conversion, _State must be set so as to allow the conversion to resume when new characters arrive.

The member function returns do_in(_State, _First1, _Last1, _Next1, First2, _Llast2, _Next2).

Example

// codecvt_in.cpp
// compile with: /EHsc
#define _INTL
#include <locale>
#include <iostream>
using namespace std;
#define LEN 90
int main( )   
{
   char* pszExt = "This is the string to be converted!";
   wchar_t pwszInt [LEN+1];
   memset(&pwszInt[0], 0, (sizeof(wchar_t))*(LEN+1));
   const char* pszNext;
   wchar_t* pwszNext;
   mbstate_t state = {0};
   locale loc("C");//English_Britain");//German_Germany
   int res = use_facet<codecvt<wchar_t, char, mbstate_t> >
     ( loc ).in( state,
          pszExt, &pszExt[strlen(pszExt)], pszNext,
          pwszInt, &pwszInt[strlen(pszExt)], pwszNext );
   pwszInt[strlen(pszExt)] = 0;
   wcout << ( (res!=codecvt_base::error) ? L"It worked! " : L"It didn't work! " )
   << L"The converted string is:\n ["
   << &pwszInt[0]
   << L"]" << endl;
   exit(-1);
}

Output

It worked! The converted string is:
 [This is the string to be converted!]

Requirements

Header: <locale>

Reference

codecvt Class

Other Resources

codecvt Members