SICStus Prolog supports character codes up to 31 bits wide where the codes are interpreted as for Unicode for the common subset.
When a character code (a “code point” in Unicode terminology) is read or written to a stream, it must be encoded into a byte sequence. The method by which each character code is encoded to or decoded from a byte sequence is called “character encoding”.
The following character encodings are currently supported by SICStus Prolog.
BEdenote respectively little endian and big endian.
These encodings can be auto-detected if a Unicode signature is present in a file opened for read. A Unicode signature is also known as a Byte order mark (BOM).
In addition, it is possible to use all alternative names defined by the IANA registry http://www.iana.org/assignments/character-sets.
All encodings in the table above, except the UTF-XXX encodings, supports
reposition(true) option to
The encoding to use can be specified when using
similar predicates using the option
encoding/1. When opening a
file for input, the encoding can often be determined automatically. The
ISO-8859-1 if no encoding is specified and no encoding
can be detected from the file contents.
The encoding used by a text stream can be queried using
See mpg-ref-open for details on how character encoding is auto-detected when opening text files.