diff options
Diffstat (limited to 'erts/doc/src/erl_ext_dist.xml')
| -rw-r--r-- | erts/doc/src/erl_ext_dist.xml | 69 |
1 files changed, 55 insertions, 14 deletions
diff --git a/erts/doc/src/erl_ext_dist.xml b/erts/doc/src/erl_ext_dist.xml index b4b245187d..712c30afc0 100644 --- a/erts/doc/src/erl_ext_dist.xml +++ b/erts/doc/src/erl_ext_dist.xml @@ -5,7 +5,7 @@ <header> <copyright> <year>2007</year> - <year>2021</year> + <year>2023</year> <holder>Ericsson AB, All Rights Reserved</holder> </copyright> <legalnotice> @@ -655,6 +655,7 @@ encoded using <c>NEW_PORT_EXT</c>, even external ports received as <seeguide marker="#PORT_EXT"><c>PORT_EXT</c></seeguide> from older nodes. </p> + </section> <section> @@ -683,8 +684,10 @@ works just like in <seeguide marker="#NEW_PID_EXT"><c>NEW_PID_EXT</c></seeguide>. Port operations are not allowed across node boundaries. </p> - <p><c>V4_PORT_EXT</c> was introduced in OTP 24, but only to be decoded - and echoed back. Not encoded for local ports. + <p>In OTP 26 distribution flag + <seeguide marker="erl_dist_protocol#DFLAG_V4_NC"><c>DFLAG_V4_NC</c></seeguide> + as well as <c>V4_PORT_EXT</c> became mandatory accepting full + 64-bit ports to be decoded and echoed back. </p> </section> @@ -742,14 +745,10 @@ <seeguide marker="#utf8_atoms">encoded as an atom</seeguide>.</p> </item> <tag><c>ID</c></tag> - <item><p>A 32-bit big endian unsigned integer. If distribution flag - <seeguide marker="erl_dist_protocol#DFLAG_V4_NC"><c>DFLAG_V4_NC</c></seeguide> - is not set, only 15 bits may be used and the rest must be 0.</p> + <item><p>A 32-bit big endian unsigned integer.</p> </item> <tag><c>Serial</c></tag> - <item><p>A 32-bit big endian unsigned integer. If distribution flag - <seeguide marker="erl_dist_protocol#DFLAG_V4_NC"><c>DFLAG_V4_NC</c></seeguide> - is not set, only 13 bits may be used and the rest must be 0.</p> + <item><p>A 32-bit big endian unsigned integer.</p> </item> <tag><c>Creation</c></tag> <item><p>A 32-bit big endian unsigned integer. All identifiers @@ -768,9 +767,10 @@ even external pids received as <seeguide marker="#PID_EXT"><c>PID_EXT</c></seeguide> from older nodes. </p> - <p>In OTP 24 distribution flag + <p>In OTP 26 distribution flag <seeguide marker="erl_dist_protocol#DFLAG_V4_NC"><c>DFLAG_V4_NC</c></seeguide> - was introduced, accepting full 64-bit pids to be decoded and echoed back. + became mandatory accepting full 64-bit pids to be decoded + and echoed back. </p> </section> @@ -1080,9 +1080,7 @@ <seeguide marker="#utf8_atoms">encoded as an atom</seeguide>.</p> </item> <tag><c>Len</c></tag> - <item><p>A 16-bit big endian unsigned integer not larger than 5 when the - <seeguide marker="erl_dist_protocol#DFLAG_V4_NC"><c>DFLAG_V4_NC</c></seeguide> - has been set; otherwise not larger than 3.</p> + <item><p>A 16-bit big endian unsigned integer not larger than 5.</p> </item> <tag><c>ID</c></tag> <item><p>A sequence of <c>Len</c> big-endian unsigned integers @@ -1104,6 +1102,9 @@ <seeguide marker="#NEW_REFERENCE_EXT"><c>NEW_REFERENCE_EXT</c></seeguide> from older nodes. </p> + <p>In OTP 26 distribution flag + <seeguide marker="erl_dist_protocol#DFLAG_V4_NC"><c>DFLAG_V4_NC</c></seeguide> + became mandatory. References now can contain up to 5 <c>ID</c> words.</p> </section> <section> @@ -1420,6 +1421,46 @@ </note> </section> + <section> + <marker id="LOCAL_EXT"/> + <title>LOCAL_EXT</title> + <table align="left"> + <row> + <cell align="center">1</cell> + <cell align="center">...</cell> + </row> + <row> + <cell align="center"><c>121</c></cell> + <cell align="center">...</cell> + </row> + <tcaption>LOCAL_EXT</tcaption></table> + <p> + Marks that this is encoded on an alternative local external term + format intended to only be decoded by a specific local decoder. + The bytes following from here on may contain any unspecified type + of encoding of terms. It is the responsibility of the user to only + attempt to decode terms on the local external term format which has + been produced by a matching encoder. + </p> + <p> + This tag is used by the Erlang runtime system upon encoding the local + external term format when the + <seeerl marker="erts:erlang#term_to_binary_local"><c>local</c></seeerl> + option is passed to + <seemfa marker="erts:erlang#term_to_binary/2"><c>term_to_binary/2</c></seemfa>, + but can be used by other encoders as well providing similar + functionality. The Erlang runtime system adds a hash immediately + following the <c>LOCAL_EXT</c> tag which is verified on decoding in + order to verify that encoder and decoder match which might be a good + practice. This will very likely catch mistakes made by users, but + is not guaranteed to, and is not intended to, prevent decoding of an + intentionally forged encoding on the local external term format. + </p> + <p> + <c>LOCAL_EXT</c> was introduced in OTP @OTP-18477@. + </p> + </section> + </chapter> |