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Extending Informix®Beyond standard relational database objects, HCL Informix® can be extended to handle specialized data types, access methods, routines, and other objects. Informix® includes many built-in extensions that are fully integrated in the database server. Informix® also provides DataBlade® modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for Informix®.
Creating extensionsYou can create user-defined data types, routines, access methods, and other database objects to suit your needs. You can use application programming interfaces to write user-defined routines and applications that access data in Informix® databases.
DataBlade® API Programmer's GuideThe Informix® DataBlade® API Programmer's Guide describes information about the DataBlade® API, the C-language application programming interface (API) provided with HCL Informix®.
Data manipulation
Numeric data typesThis section describes these numeric data types and the functions that the DataBlade® API supports to process numeric data.
Floating-point dataA floating-point value is a large decimal value that is stored in a fixed field width. Because the field width is fixed, a floating-point number that is larger than the field width only retains its most significant digits. That is, digits that do not fit into the fixed width are dropped (rounded or truncated).
Floating-point binary representationsThe DataBlade® API provides data types to support the binary representations of floating-point values.
SMALLFLOAT data typeThe SQL SMALLFLOAT data type can hold single-precision floating-point values. The DataBlade® API supports the SMALLFLOAT data type with the mi_real data type. The mi_real data type stores internal SMALLFLOAT values, as 32-bit floating-point values.

SMALLFLOAT data type

The SQL SMALLFLOAT data type can hold single-precision floating-point values. The DataBlade® API supports the SMALLFLOAT data type with the mi_real data type. The mi_real data type stores internal SMALLFLOAT values, as 32-bit floating-point values.

Server only:

Although an mi_real value can fit into an MI_DATUM structure, values of this data type are always passed by reference. Unlike other four-byte values, mi_real values cannot be passed by value. All values greater than four bytes are passed by reference.

Therefore, if a UDR is called from an SQL statement, the database server passed a pointer to any mi_real arguments; it does not pass the actual value. Similarly, if a user-defined function returns an mi_real value to an SQL statement, you must allocate space for the value, fill this space, and return a pointer to this space.

DataBlade API modules that are not invoked from SQL statements might pass mi_real values by value. However, for consistency, you might want to pass them by reference.

Client only: All data types, including mi_real, must be passed by reference within client LIBMI applications.

Important: To make your DataBlade API module portable across different architectures, it is recommended that you use the DataBlade API data type, mi_real, instead of the native C-language counterpart, float. The mi_real data type handles the different sizes of small floating-point values across computer architectures.

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