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Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
Informix® Object Interface for C++ Guide
The Informix® Object Interface for C++ Programmer's Guide describes how to develop HCL Informix client applications by using the object-oriented C++ programming language.
Appendixes
This section contains additional reference information.
The ITLocale class
This section describes the ITLocale class, which encapsulates the GLS API.
Code set conversion methods
This section describes the ITLocale methods for converting code sets.
The SizeForCodesetConversion method
This method calculates the number of bytes needed to convert the multibyte characters in nfrombytes from the code set associated with the fromLocaleName locale to the code set associated with the toLocaleName locale.

Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
- Change Data Capture API Programmer's Guide
  The Informix® Change Data Capture API Programmer's Guide describes how to program applications to process changed data from HCL Informix databases using the Informix Change Data Capture API.
- Embedded SQLJ for HCL Informix®
  The Informix® Embedded SQLJ User's Guide contains information about using Informix Embedded SQLJ.
- ESQL/C Guide
  The Informix® ESQL/C Programmer's Manual explains how to use Informix ESQL/C, the Informix implementation of Embedded Structured Query Language (SQL) for C (ESQL/C), to create client applications with database-management capabilities.
- GLS User's Guide
  The Informix® GLS User's Guide describes the Global Language Support (GLS) feature available in Informix products.
- API
  The Informix® GLS API Programmer's Guide describes the global language support (GLS) application programming interface (API) available in Informix ESQL/C and HCL Informix DataBlade® modules.
- Informix® Object Interface for C++ Guide
  The Informix® Object Interface for C++ Programmer's Guide describes how to develop HCL Informix client applications by using the object-oriented C++ programming language.
  - Architecture of the object interface for C++
    The encapsulates HCL Informix® database server features into a class hierarchy.
  - Issue database queries and retrieve results
    To interact with a database, your C++ client application uses the operation classes of the . These classes have methods for opening database connections, submitting queries, and manipulating database cursors. This section describes how to use these methods.
  - Access data values
    This section describes the specific value interfaces in detail, and shows how to modify value objects and extract information through the value interfaces into host variables in your application.
  - Create and extend value objects
    When you retrieve values from the HCL Informix® database by using the , the values are returned as value objects. Value objects are created by the Object Interface for C++ by using an extensible class factory that maps Informix data types to C++ objects.
  - Operation class reference
    This section is an alphabetized reference that lists and describes the operation classes. Each class has an assignment operator and a copy constructor, which are not listed in the tables of methods.
  - Value interface reference
    This section lists and describes the value interfaces. The ITFactoryList and ITPreserveData classes provide support for value interfaces.
  - Appendixes
    This section contains additional reference information.
    - Supported data types
      This section lists the server data types and the interfaces supported for them.
    - Example programs
    - The ITLocale class
      This section describes the ITLocale class, which encapsulates the GLS API.
      - Multibyte character string termination
      - Multibyte character termination
      - Memory allocation
      - Access the ITLocale object
      - Error return method
        This method returns a GLS error number.
      - String comparison methods
        This section describes the ITLocale methods for comparing strings.
      - String processing methods
        This section describes the ITLocale methods for processing strings.
      - Environment method
        This topic describes the ITLocale method for determining the client locale.
      - Code set conversion methods
        This section describes the ITLocale methods for converting code sets.
        The ConvertCodeset method
        This method converts the string of multibyte characters in from to another code set and copies the result to the location pointed to by to.
        The NeedToConvertCodeset method
        This method determines if conversion is necessary from the code set associated with the fromLocaleName locale to the code set associated with the toLocalename locale.
        The SizeForCodesetConversion method
        This method calculates the number of bytes needed to convert the multibyte characters in nfrombytes from the code set associated with the fromLocaleName locale to the code set associated with the toLocaleName locale.
      - Character classification methods
        This section describes the ITLocale methods for classifying characters.
      - Character case conversion methods
        This section describes the ITLocale methods for converting the case of characters.
      - Built-in data type conversion methods
        This section describes the ITLocale methods for converting built-in data types to an internal representation.
      - Multibyte and wide character conversion methods
        This section describes the ITLocale methods for converting characters and character strings between their multibyte and wide character representations.
      - Multibyte string traversal and indexing methods
        This section describes the following ITLocale methods for converting built-in data types to an internal representation.
- Informix® ODBC Driver Guide
  The Informix® ODBC Driver Programmer's Manual serves as a user guide and reference for Informix ODBC Driver, which is the Informix implementation of the Microsoft™ Open Database Connectivity (ODBC) interface, Version 3.0.
- .NET provider options
  The Data Server Provider for .NET DB2® provider option is the preferred Informix® provider for developing new applications.
- Informix 4GL
  This topic provides a link to the documentation.
- Informix® JDBC Driver Guide
  The Informix® JDBC Driver Programmer's Guide describes how to install, load, and use Informix JDBC Driver to connect to the Informix database from within a Java™ application or applet.
- Informix International Language Supplement (ILS) User Guide
  These topics include information about the translated user interface files for Informix® UNIX™ products, locales, and code set conversion tables
- Informix® OLE DB Provider Guide
  The Informix® OLE DB Provider Programmer's Guide describes the software requirements for using Informix OLE DB Provider, show how to install and configure the provider for your use, and explain how to use Informix OLE DB Provider to enable client applications, such as ActiveX Data Object (ADO) applications and web pages, to access data on the Informix server.

The SizeForCodesetConversion method

This method calculates the number of bytes needed to convert the multibyte characters in nfrombytes from the code set associated with the fromLocaleName locale to the code set associated with the toLocaleName locale.

int SizeForCodesetConversion(const char *toLocaleName, 
                              const char *fromLocaleName, 
                             int nfrombytes) const

This method returns the number of bytes to convert. If this value equals the number of bytes in nfrombytes, then conversion is done in place. Otherwise, you must allocate another buffer for the conversion.

If there is an error, this method returns -1. Call ITLocale::GetError() to retrieve a specific error message.