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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.
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.
What is Informix® ESQL/C?
Compile programs
Compiling and linking options of the esql command
Linking options
The C compiler performs the linking phase of the Informix® ESQL/C compile.
Special linking options for Windows™
Same runtime routines for version independence

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.
  - What is Informix® ESQL/C?
    - Informix® ESQL/C programming
    - Compile programs
      - Compile the Informix® ESQL/C program
        You use the esql command to compile your Informix® ESQL/C program.
      - The esql command
      - Compiling and linking options of the esql command
        Name the executable file
        You can explicitly specify the name of the executable file with the -o option.
        Set the type of executable files created (Windows™)
        Pass options to the C compiler
        The esql command processor passes any unrecognized arguments in the command line to the C compiler.
        Specify a particular C compiler (Windows™)
        Compile without linking
        Special compile options for Windows™ environments
        Linking options
        The C compiler performs the linking phase of the Informix® ESQL/C compile.
        General linking options
        Special linking options for Windows™
        Pass arguments to the linker
        On the esql command line, you can list linker arguments by prefacing them with the -l processor option.
        Pass arguments to the resource compiler
        On the esql command line, you can list resource compiler arguments by prefacing them with the -r processor option.
        ESQL/C dynamic link libraries
        Same runtime routines for version independence
      - Access the ESQL Client-interface DLL in Windows™ environments
    - Informix® ESQL/C data types
      These topics contain information about the correspondence between SQL and C data types and how to handle data types in the Informix® ESQL/C program.
    - Character and string data types
      These topics explain how to use character data types in the Informix® ESQL/C program.
    - Numeric data types
    - Time data types
      These topics explain how to use date, datetime, and interval data types in the Informix® ESQL/C program.
    - Simple large objects
      A simple large object is a large object that is stored in a blobspace on disk and is not recoverable.
    - Smart large objects
      A smart large object is a data type that stores large, non-relational data objects such as images, sound clips, documents, graphics, maps and other large objects, and allows you to perform read, write, and seek operations on those objects.
    - Complex data types
      These topics explain how to use collection and row data types in the Informix® ESQL/C program.
    - Opaque data types
      These topics explain how to use the lvarchar, fixed binary, and var binary data types to access an opaque data type from the Informix® ESQL/C program. Use these Informix ESQL/C data types to represent an opaque data type as it is transferred to and from Informix.
  - Database server communication
  - Dynamic SQL
  - Appendixes
    This section contains additional reference information.
- 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.
- 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® 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.

Same runtime routines for version independence

If your application was compiled with a version of Microsoft™ Visual C++ earlier than 4.x, you must export your C runtime library to the ESQL client-interface DLL (isqlt09a.dll). The ESQL client-interface DLL uses your runtime routines to make sure all the pieces of your application are compiled with the same runtime version. Any application that is linked to your application and calls Informix® ESQL/C library routines or SQL statements must also use your C runtime library.

To export a C runtime library, include the following line in your code before the first call to the Informix® ESQL/C library routine or SQL statement:

#include "infxcexp.c";

The infxcexp.c file contains the C code to export the addresses of all C runtime routines that the ESQL client-interface DLL uses. This file is in the %INFORMIXDIR%\incl\esql directory, which the esql command processor automatically searches when it compiles a program. If you do not use the esql command processor, add the %INFORMIXDIR%\incl\esql directory to the compiler search path before you compile.

You must include the infxcexp.c file only once, in the main() routine (once per process), before the first Informix® ESQL/C library call or SQL statement in the program. The code in this file exports your runtime library to the ESQL runtime DLL (isqlt09a.dll) so that they use the same C runtime code. Exporting your runtime routines enables the ESQL runtime routines to allocate memory (malloc()), return the pointer to a C program, and let the program free the memory (free()). It also enables a C program to open a file and to pass the handle (or file pointer) to the ESQL runtime routines for read/write access.