Home
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®.
DataBlade® API overview
Access SQL data typesThis section provides an overview of the data types that the DataBlade® API supports.
Boolean data typesBoolean data holds values to indicate two states: true and false. The DataBlade® API provides support for boolean values in both their text and binary representations.
Pointer data types (Server)The SQL POINTER data type is the SQL equivalent of a generic pointer. This data type is used in the routine registration of a UDR to indicate that some data type has no equivalent SQL data type. The DataBlade® API represents the POINTER data type with the mi_pointer data type.

Pointer data types (Server)

The SQL POINTER data type is the SQL equivalent of a generic pointer. This data type is used in the routine registration of a UDR to indicate that some data type has no equivalent SQL data type. The DataBlade® API represents the POINTER data type with the mi_pointer data type.

Use the mi_pointer data type only for communications between UDRs. The POINTER data type is a predefined opaque type (an opaque data type that HCL Informix® defines). However, no opaque-type support functions for this data type are included.

Important: Because the POINTER data type does not include opaque-type support functions, you cannot pass this type between the database server and a client application. Also, do not define columns to be of type POINTER.

The mi_pointer data type is guaranteed to be the size of the C type void * on all computer architectures. The C type void * is usually equivalent to a long type, which is usually four bytes in length.

On 64-bit platforms, void * is eight bytes in length, so mi_pointer is also eight bytes.

An mi_pointer value can fit into an MI_DATUM structure and can be passed by value to and from C UDRs. Keep in mind that because mi_pointer actually contains an address to a value, passing an mi_pointer by value is actually the same as passing the value to which mi_pointer points by reference.

Important: When you use mi_pointer, make sure that the value that the mi_pointer references is allocated with a memory duration appropriate to the use of the value.

Rate this topic

5 stars 4 stars 3 stars 2 stars 1 star

Comment on this topic.

By clicking this box, you acknowledge that you are NOT a U.S. Federal Government employee or agency, nor are you submitting information with respect to or on behalf of one. HCL provides software and services to U.S. Federal Government customers through its partners immixGroup, Inc. Contact this team at https://hcltechsw.com/resources/us-government-contact. Do not include any personal data in this Comment box.