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®.
Create user-defined routines
Write a user-defined routineThis section outlines some implementation issues for C user-defined routines (UDRs). This section also describes the specific features and tasks of a C UDR.
Perform input and outputBecause a C UDR executes in the context of the database server, it must not use the standard input/output (I/O) calls such as scanf() and printf(). The DataBlade® API provides support for I/O on a generic stream and I/O on an operating-system file from a UDR.
Access to a stream (Server)The DataBlade® API provides a stream I/O interface, which enables you to use the same function calls to access different objects. Stream is a generic term for an object that can be written to or read from.
Release stream resourcesWhen your DataBlade® API module no longer needs a stream, you need to assess whether you can release resources that the stream is using.

Release stream resources

When your DataBlade® API module no longer needs a stream, you need to assess whether you can release resources that the stream is using.

A stream descriptor that the mi_stream_init() function allocated has the current memory duration, so it remains valid until one of the following events occurs:

The mi_stream_close() function closes the stream, freeing the stream descriptor.
The current memory duration expires.

To conserve resources, use the mi_stream_close() function to deallocate the stream descriptor explicitly when your DataBlade API module no longer needs it. The mi_stream_close() function is the destructor function for a stream descriptor. This function frees a stream descriptor that mi_stream_init() allocated and any associated resources, including the stream-data buffer.

The mi_stream_close() function does not automatically free a stream descriptor allocated by your stream-open function. If the mi_stream_init() function does not allocate a stream descriptor, your type-specific implementation of mi_stream_close() must handle the deallocation.

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.