Information for UDX developers

UDX developers need to be aware of the following restrictions.

Signatures
For a UDX or SQL function, its name and the list of its input arguments comprise its signature. For example, udx42(VARCHAR,CHAR) is the signature of a UDX with the name udx42 that accepts two input arguments (one VARCHAR and one CHAR).
Overloading functions
You can create UDXs that have the same name but different signatures and return types. This process is called overloading the definition.
UDX environment
The UDX environment consists of a list of one or more variable name and value pairs that you can specify for a UDSF, UDAF, or UDTF when you register it. Using environment variables, you can conditionalize the UDX behavior in the UDX definition.
International and Unicode characters
UDXs in table columns and views
Data type declarations for input arguments and return values
The data type declarations for the input arguments and return value of a UDX fall into one of three categories: fixed size, any size, and variable.

Parent topic: Creating UDX source files in C++