The sysroutinelangs system catalog table lists the supported programming languages for user-defined routines (UDRs). It has these columns.
Column Type Explanation
langid SERIAL Code uniquely identifying a supported language
langname CHAR(30) Name of the language, such as C or SPL
langinitfunc VARCHAR(128) Name of initialization function for the language
langpath CHAR(255) Directory path for the UDR language
langclass CHAR(18) Name of the class of the UDR language

An index on the langname column allows duplicate values.