The RPG IV language is based on the EBCDIC character set, but also supports UTF-8, UTF-16 and many other character sets. The threadsafe aspects of the language are considered idiosyncratic by some as the compiler team has addressed threads by giving each thread its own static storage, rather than make the RPG run-time environment re-entrant. This has been noted to muddle the distinction between a thread and a process (making RPG IV threads a kind of hybrid between threads and processes).