Refers to the atom with AtomCacheReferenceIndex in the distribution header.

Unsigned 8 bit integer.

Signed 32 bit integer in big-endian format (i.e. MSB first)

A float is stored in string format. the format used in sprintf to format the float is "%.20e" (there are more bytes allocated than necessary). To unpack the float use sscanf with format "%lf".

This term is used in minor version 0 of the external format; it has been superseded by NEW_FLOAT_EXT .

An atom is stored with a 2 byte unsigned length in big-endian order, followed by Len numbers of 8 bit Latin1 characters that forms the AtomName. Note: The maximum allowed value for Len is 255.

Encode a reference object (an object generated with make_ref/0). The Node term is an encoded atom, i.e. ATOM_EXT, SMALL_ATOM_EXT or ATOM_CACHE_REF. The ID field contains a big-endian unsigned integer, but should be regarded as uninterpreted data since this field is node specific. Creation is a byte containing a node serial number that makes it possible to separate old (crashed) nodes from a new one.

In ID, only 18 bits are significant; the rest should be 0. In Creation, only 2 bits are significant; the rest should be 0. See NEW_REFERENCE_EXT.

Encode a port object (obtained form open_port/2). The ID is a node specific identifier for a local port. Port operations are not allowed across node boundaries. The Creation works just like in REFERENCE_EXT.

Encode a process identifier object (obtained from spawn/3 or friends). The ID and Creation fields works just like in REFERENCE_EXT, while the Serial field is used to improve safety. In ID, only 15 bits are significant; the rest should be 0.

SMALL_TUPLE_EXT encodes a tuple. The Arity field is an unsigned byte that determines how many element that follows in the Elements section.

Same as SMALL_TUPLE_EXT with the exception that Arity is an unsigned 4 byte integer in big endian format.

MAP_EXT encodes a map. The Arity field is an unsigned 4 byte integer in big endian format that determines the number of key-value pairs in the map. Key and value pairs (Ki => Vi) are encoded in the Pairs section in the following order: K1, V1, K2, V2,..., Kn, Vn. Duplicate keys are not allowed within the same map.

Since: OTP 17.0

The representation for an empty list, i.e. the Erlang syntax [].

String does NOT have a corresponding Erlang representation, but is an optimization for sending lists of bytes (integer in the range 0-255) more efficiently over the distribution. Since the Length field is an unsigned 2 byte integer (big endian), implementations must make sure that lists longer than 65535 elements are encoded as LIST_EXT.

Length is the number of elements that follows in the Elements section. Tail is the final tail of the list; it is NIL_EXT for a proper list, but may be anything type if the list is improper (for instance [a|b]).

Binaries are generated with bit syntax expression or with list_to_binary/1, term_to_binary/1, or as input from binary ports. The Len length field is an unsigned 4 byte integer (big endian).

Bignums are stored in unary form with a Sign byte that is 0 if the binum is positive and 1 if is negative. The digits are stored with the LSB byte stored first. To calculate the integer the following formula can be used:
B = 256
(d0*B^0 + d1*B^1 + d2*B^2 + ... d(N-1)*B^(n-1))

Same as SMALL_BIG_EXT with the difference that the length field is an unsigned 4 byte integer.

Node and Creation are as in REFERENCE_EXT.

ID contains a sequence of big-endian unsigned integers (4 bytes each, so N' is a multiple of 4), but should be regarded as uninterpreted data.

N' = 4 * Len.

In the first word (four bytes) of ID, only 18 bits are significant, the rest should be 0. In Creation, only 2 bits are significant, the rest should be 0.

NEW_REFERENCE_EXT was introduced with distribution version 4. In version 4, N' should be at most 12.

See REFERENCE_EXT).

An atom is stored with a 1 byte unsigned length, followed by Len numbers of 8 bit Latin1 characters that forms the AtomName. Longer atoms can be represented by ATOM_EXT. Note the SMALL_ATOM_EXT was introduced in erts version 5.7.2 and require an exchange of the DFLAG_SMALL_ATOM_TAGS distribution flag in the distribution handshake.

This is the new encoding of internal funs: fun F/A and fun(Arg1,..) -> ... end.

This term is the encoding for external funs: fun M:F/A.

Module and Function are atoms (encoded using ATOM_EXT, SMALL_ATOM_EXT or ATOM_CACHE_REF).

Arity is an integer encoded using SMALL_INTEGER_EXT.

This term represents a bitstring whose length in bits does not have to be a multiple of 8. The Len field is an unsigned 4 byte integer (big endian). The Bits field is the number of bits (1-8) that are used in the last byte in the data field, counting from the most significant bit towards the least significant.

A float is stored as 8 bytes in big-endian IEEE format.

This term is used in minor version 1 of the external format.

An atom is stored with a 2 byte unsigned length in big-endian order, followed by Len bytes containing the AtomName encoded in UTF-8.

For more information on encoding of atoms, see note on UTF-8 encoded atoms in the beginning of this document.

An atom is stored with a 1 byte unsigned length, followed by Len bytes containing the AtomName encoded in UTF-8. Longer atoms encoded in UTF-8 can be represented using ATOM_UTF8_EXT.

For more information on encoding of atoms, see note on UTF-8 encoded atoms in the beginning of this document.