The DataIO API (application programming interfaces) is a component of the eCognition Developer software development kit (SDK). The DataIO API can be used to develop drivers, or plug-ins for data connectivity and integration. You can build a connector to many kinds of things; a particular kind of file system, a binary image format, database, and more.
This DataIO API User Guide provides general instruction about using the DataIO API.
In the related DataIO API reference help file you find detailed information about classes and functions that make up drivers and connectors, including some guidance.
Go to the folder SDK, which is installed in the eCognition Developer installation directory. The default path is C:\Program Files\eCognition Developer [Version Number]\SDK\DataIO\Help\DataIOAPI_Help.chm.