The language constants are defined in e32const.h.

Define the languages that your component is localized to in your .mmp file:

// file: MyApp.mmp
 
...
 
LANG 01 02 16 // UK English, French, Russian

Place logical strings for different languages in different language-specific files. Dont forget to define the file encoding for those languages that use character sets beyond basic ASCII. For instance:

// file: MyApp.l01 (ELangEnglish = 01)
 
#define message_wait     "Please wait..."
#define mess_with_param  ¨You have %N new messages.¨

// file: MyApp.l02 (ELangFrench = 02)
 
// the file has to be encoded in UTF-8 for the strings to be rendered correctly:
CHARACTER_SET UTF8 
 
#define message_wait   "Attendez, s'il-vous plait..."
#define mess_with_param  ¨Vous avez %N nouveaux messages.¨

// file: MyApp.l16 (ELangRussian = 16)
 
// the file has to be encoded in UTF-8 for the strings to be rendered correctly:
CHARACTER_SET UTF8
 
#define message_wait   "Пожалуйста, подождите ..."
#define mess_with_param  ¨Количество новых сообщений: %N¨

In file MyApp.loc, include the correct language-specific file:

// file: MyApp.loc
CHARACTER_SET UTF8
 
#if defined LANGUAGE_01
  #include "MyApp.l01"
#elif defined LANGUAGE_02
  #include "MyApp.l02"
#elif defined LANGUAGE_16
  #include "MyApp.l16"
#endif

In MyApp.rss, define the resources based on the strings defined in the language-specific file that was included by MyApp.loc:

// file: MyApp.rss
#include <eikon.rh>
#include "MyApp.loc"
 
RESOURCE TBUF r_message_wait { buf = message_wait; }
RESOURCE TBUF r_mess_with_param { buf = mess_with_param; }

In your code, use the localized strings as follows. The string denoted by R_MESSAGE_WAIT will be displayed in the appropriate language. Note the change from lower-case to upper-case.

//file: testexample.cpp
#include <stringloader.h>
...
...
 
// how to load simple message
HBufC* message = StringLoader::LoadL( R_MESSAGE_WAIT );
 
 
// how to load message with params
TInt msgCount = 10;
message = StringLoader::LoadL( R_MESS_WITH_PARAM, msgCount ); //  You have 10 new messages.
 
CAknInformationNote* note = new ( ELeave ) CAknInformationNote( ETrue );
note->ExecuteLD( *message );
delete message;

Finally, add the localized language resources to the package file:

• if you want to support only current langauge of the device, use following approach:

;; file: MyApp.pkg 
 
...
 
; languages supported:
&EN,FR,RU
 
; localization:
{
"$(EPOCROOT)epoc32\data\z\resource\apps\MyApp.r01"
"$(EPOCROOT)epoc32\data\z\resource\apps\MyApp.r02"
"$(EPOCROOT)epoc32\data\z\resource\apps\MyApp.r16"
}-"!:\resource\apps\MyApp.rsc"

• if you want to allow user select necessary languages, you could use following approach:

;; file: MyApp.pkg 
 
...
 
; languages supported:
&EN,FR,RU
 
; localization:
 
!({¨English¨, ¨English¨, ¨English¨ }, { ¨French¨, ¨French¨, ¨French¨ }, { ¨Russian¨, ¨Russian¨,¨Russian¨ })
 
IF (Option1)
    "$(EPOCROOT)epoc32\data\z\resource\apps\MyApp.r01"-"!:\resource\apps\MyApp.r01"
ENDIF
 
IF (Option2)
    "$(EPOCROOT)epoc32\data\z\resource\apps\MyApp.r02"-"!:\resource\apps\MyApp.r02"
ENDIF
 
IF (Option3)
    "$(EPOCROOT)epoc32\data\z\resource\apps\MyApp.r03"-"!:\resource\apps\MyApp.r03"
ENDIF

There are two ways to add localized resource files into a .pkg file and generate the SIS package. Read Knowledge Base article for details.