# Interfaces to Other Languages

These are the available functions for interfaces to other languages. See each function's help topic in the TERR Language Reference for more information.

Function name | Title description
--- | ---
`.C` | Call a Fortran or C Routine
`.Call` | Manipulate R objects from C code
`.External` | Manipulate R objects from C code
`.External2` | Manipulate R objects from C code
`.Fortran` | Call a Fortran or C Routine
`as.double` | Double Precision Objects
`as.double.difftime` | Double Precision Objects
`as.double.POSIXlt` | Double Precision Objects
`as.single` | Single Precision Objects
`as.single.default` | Single Precision Objects
`double` | Double Precision Objects
`dyn.load` | Foreign Function Interface
`dyn.unload` | Foreign Function Interface
`getNativeSymbolInfo` | Obtain a Description of one or more Native Symbols
`is.double` | Double Precision Objects
`is.loaded` | Foreign Function Interface
`is.single` | Single Precision Objects
`NativeSymbol` | Obtain a Description of one or more Native Symbols
`NativeSymbolInfo` | Obtain a Description of one or more Native Symbols
`RegisteredNativeSymbol` | Obtain a Description of one or more Native Symbols
`single` | Single Precision Objects
`system` | Invoke a System Command
`system2` | Invoke a System Command (Windows only at this time)