ABAP and Unicode 
From Release 6.10, ABAP supports multi-byte coding for characters in Unicode. Prior to Release 6.10, ABAP used only character sets that were based on single-byte codes ? such as ASCII and EBCDIC ? or double-byte codes, such as SJIS and BIG5.
This switch to Unicode affects all statements where an explicit or implicit assumption is made about the internal length of a character. If you use these statements in a program that is designed to exploit the Unicode capabilities of the runtime environment, they must be checked and changed if necessary. Once a Unicode-enabled program has been changed accordingly, it behaves in the same way in both Unicode and non-Unicode systems. You can develop programs in a non-Unicode system (NUS) and then import them into a Unicode system (US). The following sections describe the conversions that are necessary:
Character Codes ABAP Development Under Unicode Concepts and Conventions Restrictions in Unicode Programs New ABAP Statements for Unicode New Classes for Unicode RFC and Unicode Other Measures Other Sample Programs Unicode Glossary
ABAP Development Under Unicode 
A Unicode-enabled ABAP program (UP) is a program in which all Unicode checks are effective. Such a program returns the same results in a non-Unicode system (NUS) as in a Unicode system (US). In order to perform the relevant syntax checks, you must activate the Unicode flag in the screens of the program and class attributes.
In a US, you can only execute programs for which the Unicode flag is set. In future, the Unicode flag must be set for all SAP programs to enable them to run on a US. If the Unicode flag is set for a program, the syntax is checked and the program executed according to the rules described in this document, regardless of whether the system is a US or an NUS. From now on, the Unicode flag must be set for all new programs and classes that are created.
If the Unicode flag is not set, a program can only be executed in an NUS. The syntactical and semantic changes described below do not apply to such programs. However, you can use all language extensions that have been introduced in the process of the conversion to Unicode.
As a result of the modifications and restrictions associated with the Unicode flag, programs are executed in both Unicode and non-Unicode systems with the same semantics to a large degree. In rare cases, however, differences may occur. Programs that are designed to run on both systems therefore need to be tested on both platforms.
You are recommended to follow the procedure below to make your programs US-compliant:
- The UNICODE task in transaction SAMT performs first an NUS and then a US syntax check for a selected program set. For an overview of the syntax errors by systems, programs and authors, consult the following document in SAPNet: Alternatively, you can start the ABAP program RSUNISCAN_FINAL to determine the Unicode-relevant syntax errors for a single program.
- Before you can set the Unicode flag in the NUS in the attributes of the program concerned, all syntax errors must be removed.
- Having enabled the Unicode flag in the NUS, you can run the syntax check for this program. To display a maximum of 50 syntax errors simultaneously, choose Utilities -> Settings -> Editor in the ABAP Editor and select the corresponding checkbox.
- Once all syntactical requirements are met in the NUS, you must test the program both in the NUS and US. The purpose of this test is to recognize any runtime errors and make sure that the results are correct in both systems. To rule out runtime errors in advance, you should always type field symbols and parameters so that any potential problems can be detected during the syntax check.
