• between Unicode and other native character sets
• from a native character set to another native character set.

#include <iconv.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

int main (void)
{
 iconv_t cd;
 const char *inbuf = "abcd";
 char *outbuf = NULL;;
 size_t inbytes,outbytes;
 cd = iconv_open ("ISO-8859-2", "ISO-8859-1");
 if (cd == (iconv_t) -1)
 {
   printf ("iconv_open failed errno = %d\n",errno);
   iconv_close(cd);
   return 1;
 }
 outbuf = (char*) malloc(4);
 inbytes = outbytes = 4 ;
 iconv (cd, &inbuf, &inbytes, &outbuf, &outbytes);
 if (iconv (cd, &inbuf, &inbytes, &outbuf, &outbytes) == (size_t) -1)
     printf(" errno = %d \n",errno);
 else
       printf("Iconv passed\n");
 iconv_close (cd);
 return 1;
}

• Specify the non-Unicode character set being converted to Unicode. In this case it is ISO-8859-1.
• Convert the text from the native character set to Unicode.
• Specify the non-Unicode character set being converted from Unicode. In this case it is ISO-8859-2
• Convert the text from Unicode to the native character set

#include <e32base.h>
#include <e32cons.h>
#include <charconv.h>
#include <f32file.h>
#include <string.h>
#include <stdlib.h>
LIT8(KNativeText, "abcd");
LOCAL_C int doExampleL()
{
   char *inbuf = "abcd";
   char *outbuf = NULL;
   int inbytes,outbytes;
   inbytes = outbytes = 4; 
   
   TInt retVal = KErrNone;
   outbuf = (char*) malloc(outbytes);
   RFs fileSession;
   User::LeaveIfError(fileSession.Connect());
   CleanupClosePushL(fileSession);
  
  //Allocates and constructs a CCnvCharacterSetConverter object
  CnvCharacterSetConverter* conv = CCnvCharacterSetConverter::NewLC() ;
  TPtrC8 remainderOfForeignText((const TText8*) inbuf,inbytes);
  TBuf16<256> UnicodeText;
  TBuf8<256> outputBuffer;
  TInt numberOfUnconvertibleCharacters = 0;
  TInt indexOfFirstByteOfFirstUnconvertibleCharacter = 0;
  //Specifies the character set(ISO-8859-1) to convert to UNICODE
  CCnvCharacterSetConverter::TAvailability  avail = conv->PrepareToConvertToOrFromL (KCharacterSetIdentifierIso88591, fileSession);
 if(CCnvCharacterSetConverter::ENotAvailable == avail)
 {
   CleanupStack::PopAndDestroy(2);  //conv, fileSession
   return KErrGeneral;
 }
 //Convert text encoded in the ISO-8859-1 character set into the Unicode character set (UCS-2).
 retVal = conv->ConvertToUnicode(UnicodeText, remainderOfForeignText, numberOfUnconvertibleCharacters, indexOfFirstByteOfFirstUnconvertibleCharacter);
 if(retVal < 0 && (retVal != CCnvCharacterSetConverter::EErrorIllFormedInput))
 {
  CleanupStack::PopAndDestroy(2);  //conv, fileSession
  return retVal;
 }
 //Specifies the character set(ISO-8859-2) to convert from UNICODE
 avail = conv->PrepareToConvertToOrFromL(KCharacterSetIdentifierIso88592, fileSession);
 if(CCnvCharacterSetConverter::ENotAvailable == avail)
 {
   CleanupStack::PopAndDestroy(2);  //conv, fileSession
   return KErrGeneral;
 }
 //Convert text encoded in the Unicode character set (UCS-2) to  ISO-8859-2
 retVal = conv->ConvertFromUnicode(outputBuffer,UnicodeText, numberOfUnconvertibleCharacters, indexOfFirstByteOfFirstUnconvertibleCharacter);
 if(retVal < 0 && (retVal != CCnvCharacterSetConverter::EErrorIllFormedInput))
 {
   CleanupStack::PopAndDestroy(2);  //conv, fileSession
   return retVal;
 }
 TInt outputbufferLength = outputBuffer.Length();
 strncpy(outbuf, (const char*) outputBuffer.Ptr(),outputbufferLength);
 outbuf = outbuf + outputbufferLength;
 CleanupStack::PopAndDestroy(2); //conv, fileSession
 return retVal;
}