Write opaque-type support functions
The database server does not know the internal representation of an opaque type. To handle the internal representation, you write opaque-type support functions. These support functions tell the database server how to interact with the opaque type.
The following table summarizes the opaque-type support
functions.
| Category of support function | Opaque-type support functions | More information |
|---|---|---|
| Support functions as casts | input, output receive, send, import, export importbin, exportbin | Support functions as casts |
| Stream support functions | streamwrite(), streamread() | Stream support functions |
| Disk-storage support functions | assign(), destroy() | Disk-storage support functions |
| Other support functions | compare(), deepcopy(), update() | The HCL Informix User-Defined Routines and Data Types Developer's Guide |
Tip: The HCL Informix® BladeSmith
development tool, which is part of the Informix DataBlade Developers Kit (DBDK), automatically
generates some of the C source code for the support routines of an
opaque type. For more information, see the HCL
Informix
DataBlade Developers Kit User's Guide.
The following sections provide information specific to the development of the opaque-type support functions as C UDRs. For a general discussion of opaque-type support functions, see the HCL Informix User-Defined Routines and Data Types Developer's Guide.