Develop user-defined functions to work with SAP Sybase IQ databases.
The EXTFN_V3_API and EXTFN_V4_API provide callback functions enabling the UDF to write to the message file (.iqmsg).
UDFs should manage memory and temporary results as defined by the EXTFN_V3_API and EXTFN_V4_API.
SAP Sybase IQ is a multiuser application. Many users can simultaneously execute the same UDF. Certain OLAP queries cause a UDF to be executed multiple times within the same query, sometimes in parallel. For details on setting UDFs to run in parallel, see Aggregate UDF calling patterns.
To support multiple languages, UDFs should also be internationalized. In general, most UDFs operate on numeric data. In some cases, a UDF may accept string keywords as one or more of the parameters. Place these keywords in external files, in addition to any exception text and log messages used by the UDF.
SAP Sybase IQ has also been localized for a few non-English languages. To support localization to the same languages that SAP Sybase IQ supports, internationalize UDFs so that an independent organization can localize them at a later date.
For details about international language support in SAP Sybase IQ, see International Languages and Character Sets in Administration: Globalization .
See also Debugging Using Cross-Character-Set Maps at www.Sybase.com. This paper discusses how to debug with multi byte data, as opposed to input keywords, exception messages, and log entries.