Procedures:
D.15.21.1 openSSI Opens an SSI file for reading or writing. D.15.21.2 writeSSI Writes data to an SSI file. D.15.21.3 readSSI Reads data from an SSI file. D.15.21.4 closeSSI Closes an SSI file link. D.15.21.5 writeDataToSSI Writes a list of expressions to an SSI file. D.15.21.6 readDataFromSSI Reads all expressions from an SSI file. D.15.21.7 appendDataToSSI Appends a list of expressions to an SSI file.