diff options
Diffstat (limited to 'erts/doc')
| -rw-r--r-- | erts/doc/src/Makefile | 2 | ||||
| -rw-r--r-- | erts/doc/src/alt_dist.xml | 736 | ||||
| -rw-r--r-- | erts/doc/src/erl.xml | 42 | ||||
| -rw-r--r-- | erts/doc/src/erl_dist_protocol.xml | 70 | ||||
| -rw-r--r-- | erts/doc/src/erl_nif.xml | 284 | ||||
| -rw-r--r-- | erts/doc/src/erlang.xml | 230 | ||||
| -rw-r--r-- | erts/doc/src/notes.xml | 122 | ||||
| -rw-r--r-- | erts/doc/src/zlib.xml | 227 |
8 files changed, 1580 insertions, 133 deletions
diff --git a/erts/doc/src/Makefile b/erts/doc/src/Makefile index b96cbbce40..444adf4a6e 100644 --- a/erts/doc/src/Makefile +++ b/erts/doc/src/Makefile @@ -173,6 +173,8 @@ release_docs_spec: docs "$(RELSYSDIR)/doc/html" $(INSTALL_DATA) $(ERL_TOP)/erts/example/time_compat.erl \ "$(RELSYSDIR)/doc/html" + $(INSTALL_DATA) $(ERL_TOP)/lib/kernel/examples/gen_tcp_dist/src/gen_tcp_dist.erl \ + "$(RELSYSDIR)/doc/html" $(INSTALL_DATA) $(INFO_FILE) "$(RELSYSDIR)" $(INSTALL_DIR) "$(RELEASE_PATH)/man/man3" $(INSTALL_DATA) $(MAN3DIR)/* "$(RELEASE_PATH)/man/man3" diff --git a/erts/doc/src/alt_dist.xml b/erts/doc/src/alt_dist.xml index be969a8267..d3731a5391 100644 --- a/erts/doc/src/alt_dist.xml +++ b/erts/doc/src/alt_dist.xml @@ -47,23 +47,30 @@ runs on. The reason the C code is not made portable, is simply readability.</p> - <note> - <p>This section was written a long time ago. Most of it is still - valid, but some things have changed since then. - Most notably is the driver interface. Some updates have been made - to the documentation of the driver presented here, - but more can be done and is planned for the future. - The reader is encouraged to read the - <seealso marker="erl_driver"><c>erl_driver</c></seealso> and - <seealso marker="driver_entry"><c>driver_entry</c></seealso> - documentation also.</p> - </note> - <section> <title>Introduction</title> <p>To implement a new carrier for the Erlang distribution, the main steps are as follows.</p> + <note><p> + As of ERTS version 10.0 support for distribution controller + processes has been introduced. That is, the traffic over a + distribution channel can be managed by a process instead of + only by a port. This makes it possible to implement large + parts of the logic in Erlang code, and you perhaps do not + even need a new driver for the protocol. One example could + be Erlang distribution over UDP using <c>gen_udp</c> (your + Erlang code will of course have to take care of retranspissions, + etc in this example). That is, depending on what you want + to do you perhaps do not need to implement a driver at all + and can then skip the driver related sections below. + The <c>gen_tcp_dist</c> example described in the + <seealso marker="#distribution_module">Distribution + Module</seealso> section utilize distribution controller + processes and can be worth having a look at if you want to + use distribution controller processes. + </p></note> + <section> <title>Writing an Erlang Driver</title> <p>First, the protocol must be available to the Erlang machine, which @@ -152,7 +159,712 @@ </section> <section> + <marker id="distribution_module"/> + <title>Distribution Module</title> + <p> + The distribution module expose an API that <c>net_kernel</c> call + in order to manage connections to other nodes. The module name + should have the suffix <c>_dist</c>. + </p> + <p> + The module needs to create some kind of listening entity (process + or port) and an acceptor process that accepts incoming connections + using the listening entity. For each connection, the module at least + needs to create one connection supervisor process, which also is + responsible for the handshake when setting up the connection, and + a distribution controller (process or port) responsible for + transport of data over the connection. The distribution controller + and the connection supervisor process should be linked together + so both of them are cleaned up when the connection is taken down. + </p> + <p> + Note that there need to be exactly one distribution controller + per connection. A process or port can only be distribution + controller for one connection. The registration as distribution + controller cannot be undone. It will stick until the distribution + controller terminates. The distribution controller should not + ignore exit signals. It is allowed to trap exits, but it should + then voluntarily terminate when an exit signal is received. + </p> + <p> + An example implementation of a distribution module can be found + in + <url href="gen_tcp_dist.erl">$ERL_TOP/lib/kernel/examples/gen_tcp_dist/src/gen_tcp_dist.erl</url>. + It implements the distribution over TCP/IP using the <c>gen_tcp</c> + API with distribution controllers implemented by processes. This + instead of using port distribution controllers as the ordinary TCP/IP + distribution uses. + </p> + + <section> + <marker id="distribution_module_exported_callback_functions"/> + <title>Exported Callback Functions</title> + + <p> + The following functions are mandatory: + </p> + <taglist> + <tag><marker id="listen"/><c>listen(Name) -></c><br/> <c>{ok, {Listen, Address, Creation}} | {error, Error} </c></tag> + <item> + <p> + <c>listen/1</c> is called once in order to listen for incoming + connection requests. The call is made when the distribution is brought + up. The argument <c>Name</c> is the part of the node name before + the <c>@</c> sign in the full node name. It can be either an atom or a + string. + </p> + <p> + The return value consists of a <c>Listen</c> handle (which is + later passed to the <seealso marker="#accept"><c>accept/1</c></seealso> + callback), <c>Address</c> which is a <c>#net_address{}</c> record + with information about the address for the node (the + <c>#net_address{}</c> record is defined in + <c>kernel/include/net_address.hrl</c>), and <c>Creation</c> which + (currently) is an integer <c>1</c>, <c>2</c>, or <c>3</c>. + </p> + <p> + If <seealso marker="erts:epmd"><c>epmd</c></seealso> is to be used + for node discovery, you typically want to use the (unfortunately + undocumented) <c>erl_epmd</c> module (part of the <c>kernel</c> + application) in order to register the listen port with <c>epmd</c> + and retrieve <c>Creation</c> to use. + </p> + </item> + + <tag><marker id="accept"/><c>accept(Listen) -></c><br/> <c>AcceptorPid</c></tag> + <item> + <p> + <c>accept/1</c> should spawn a process that accepts connections. This + process should preferably execute on <c>max</c> priority. The process + identifier of this process should be returned. + </p> + <p> + The <c>Listen</c> argument will be the same as the <c>Listen</c> handle + part of the return value of the + <seealso marker="#listen"><c>listen/1</c></seealso> callback above. + <c>accept/1</c> is called only once when the distribution protocol is + started. + </p> + <p> + The caller of this function is a representative for <c>net_kernel</c> + (this may or may not be the process registered as <c>net_kernel</c>) + and is in this document identified as <c>Kernel</c>. + When a connection has been accepted by the acceptor process, it needs + to inform <c>Kernel</c> about the accepted connection. This is done by + passing a message on the form: + </p> + <code type="none"><![CDATA[Kernel ! {accept, AcceptorPid, DistController, Family, Proto}]]></code> + <p> + <c>DistController</c> is either the process or port identifier + of the distribution controller for the connection. The + distribution controller should be created by the acceptor + processes when a new connection is accepted. Its job is to + dispatch traffic on the connection. + </p> + <c>Kernel</c> responds with one of the following messages: + <taglist> + <tag><c>{Kernel, controller, SupervisorPid}</c></tag> + <item> + <p> + The request was accepted and <c>SupervisorPid</c> is the + process identifier of the connection supervisor process + (which is created in the + <seealso marker="#accept_connection"><c>accept_connection/5</c></seealso> + callback). + </p> + </item> + <tag><c>{Kernel, unsupported_protocol}</c></tag> + <item> + <p> + The request was rejected. This is a fatal error. The acceptor + process should terminate. + </p> + </item> + </taglist> + <p> + When an accept sequence has been completed the acceptor process + is expected to continue accepting further requests. + </p> + </item> + + <tag><marker id="accept_connection"/><c>accept_connection(AcceptorPid, DistCtrl, MyNode, Allowed, SetupTime) -></c><br/> <c>ConnectionSupervisorPid</c></tag> + <item> + <p> + <c>accept_connection/5</c> should spawn a process that will + perform the Erlang distribution handshake for the connection. + If the handshake successfully completes it should continue to + function as a connection supervisor. This process + should preferably execute on <c>max</c> priority. + </p> + <p>The arguments:</p> + <taglist> + <tag><c>AcceptorPid</c></tag> + <item> + <p> + Process identifier of the process created by the + <seealso marker="#accept"><c>accept/1</c></seealso> + callback. + </p> + </item> + <tag><c>DistCtrl</c></tag> + <item> + <p>The identifier of the distribution controller identifier + created by the acceptor process. To be passed along to + <c>dist_util:handshake_other_started(HsData)</c>. + </p> + </item> + <tag><c>MyNode</c></tag> + <item> + <p> + Node name of this node. To be passed along to + <c>dist_util:handshake_other_started(HsData)</c>. + </p> + </item> + <tag><c>Allowed</c></tag> + <item> + <p> + To be passed along to + <c>dist_util:handshake_other_started(HsData)</c>. + </p> + </item> + <tag><c>SetupTime</c></tag> + <item> + <p> + Time used for creating a setup timer by a + call to <c>dist_util:start_timer(SetupTime)</c>. + The timer should be passed along to + <c>dist_util:handshake_other_started(HsData)</c>. + </p> + </item> + </taglist> + <p> + The created process should provide callbacks and other + information needed for the handshake in a + <seealso marker="#hs_data_record"><c>#hs_data{}</c></seealso> + record and call <c>dist_util:handshake_other_started(HsData)</c> + with this record. + </p> + <p> + <c>dist_util:handshake_other_started(HsData)</c> will perform + the handshake and if the handshake successfully completes this + process will then continue in a connection supervisor loop + as long as the connection is up. + </p> + </item> + + <tag><marker id="setup"/><c>setup(Node, Type, MyNode, LongOrShortNames, SetupTime) -></c><br/> <c>ConnectionSupervisorPid</c></tag> + <item> + <p> + <c>setup/5</c> should spawn a process that connects to + <c>Node</c>. When connection has been established it should + perform the Erlang distribution handshake for the connection. + If the handshake successfully completes it should continue to + function as a connection supervisor. This process + should preferably execute on <c>max</c> priority. + </p> + <p>The arguments:</p> + <taglist> + <tag><c>Node</c></tag> + <item> + <p> + Node name of remote node. To be passed along to + <c>dist_util:handshake_we_started(HsData)</c>. + </p> + </item> + <tag><c>Type</c></tag> + <item> + <p> + Connection type. To be passed along to + <c>dist_util:handshake_we_started(HsData)</c>. + </p> + </item> + <tag><c>MyNode</c></tag> + <item> + <p> + Node name of this node. To be passed along to + <c>dist_util:handshake_we_started(HsData)</c>. + </p> + </item> + <tag><c>LongOrShortNames</c></tag> + <item> + <p> + Either the atom <c>longnames</c> or + the atom <c>shortnames</c> indicating + whether long or short names is used. + </p> + </item> + <tag><c>SetupTime</c></tag> + <item> + <p> + Time used for creating a setup timer by a + call to <c>dist_util:start_timer(SetupTime)</c>. + The timer should be passed along to + <c>dist_util:handshake_we_started(HsData)</c>. + </p> + </item> + </taglist> + <p> + The caller of this function is a representative for <c>net_kernel</c> + (this may or may not be the process registered as <c>net_kernel</c>) + and is in this document identified as <c>Kernel</c>. + </p> + <p> + This function should, besides spawning the connection supervisor, + also create a distribution controller. The distribution + controller is either a process or a port which is responsible + for dispatching traffic. + </p> + <p> + The created process should provide callbacks and other + information needed for the handshake in a + <seealso marker="#hs_data_record"><c>#hs_data{}</c></seealso> + record and call <c>dist_util:handshake_we_started(HsData)</c> + with this record. + </p> + <p> + <c>dist_util:handshake_we_started(HsData)</c> will perform + the handshake and the handshake successfully completes this + process will then continue in a connection supervisor loop + as long as the connection is up. + </p> + </item> + + <tag><marker id="close"/><c>close(Listen) -></c><br/> <c>void()</c></tag> + + <item><p> + Called in order to close the <c>Listen</c> handle + that originally was passed from the + <seealso marker="#listen"><c>listen/1</c></seealso> callback. + </p></item> + + <tag><marker id="select"/><c>select(NodeName) -></c><br/> <c>boolean()</c></tag> + <item> + <p>Return <c>true</c> if the host name part + of the <c>NodeName</c> is valid for use + with this protocol; otherwise, <c>false</c>. + </p> + </item> + + </taglist> + + <p> + There are also two optional functions that may be + exported: + </p> + <taglist> + <tag><marker id="select"/><c>setopts(Listen, Opts) -></c><br/> <c>ok | {error, Error}</c></tag> + <item> + <p> + The argument <c>Listen</c> is the handle originally passed + from the + <seealso marker="#listen"><c>listen/1</c></seealso> callback. + The argument <c>Opts</c> is a list of options to set on future + connections. + </p> + </item> + + <tag><marker id="select"/><c>getopts(Listen, Opts) -></c><br/> <c>{ok, OptionValues} | {error, Error}</c></tag> + <item> + <p> + The argument <c>Listen</c> is the handle originally passed + from the + <seealso marker="#listen"><c>listen/1</c></seealso> callback. + The argument <c>Opts</c> is a list of options to read for future + connections. + </p> + </item> + </taglist> + + </section> + <section> + <marker id="hs_data_record"/> + <title>The #hs_data{} Record</title> + <p> + The <c>dist_util:handshake_we_started/1</c> and + <c>dist_util:handshake_other_started/1</c> functions + takes a <c>#hs_data{}</c> record as argument. There + are quite a lot of fields in this record that you + need to set. The record is defined in + <c>kernel/include/dist_util.hrl</c>. Not documented + fields should not be set, i.e., should be left as + <c>undefined</c>. + </p> + <p> + The following <c>#hs_data{}</c> record fields need + to be set unless otherwise stated:</p> + <taglist> + <tag><marker id="hs_data_kernel_pid"/><c>kernel_pid</c></tag> + <item> + <p> + Process identifier of the <c>Kernel</c> process. That is, + the process that called either + <seealso marker="#setup"><c>setup/5</c></seealso> or + <seealso marker="#accept_connection"><c>accept_connection/5</c></seealso>. + </p> + </item> + + <tag><marker id="hs_data_other_node"/><c>other_node</c></tag> + <item> + <p>Name of the other node. This field is only + mandatory when this node initiates the connection. + That is, when connection is set up via + <seealso marker="#setup"><c>setup/5</c></seealso>. + </p> + </item> + + <tag><marker id="hs_data_this_node"/><c>this_node</c></tag> + <item> + <p> + The node name of this node. + </p> + </item> + + <tag><marker id="hs_data_socket"/><c>socket</c></tag> + <item> + <p> + The identifier of the distribution controller. + </p> + </item> + + <tag><marker id="hs_data_timer"/><c>timer</c></tag> + <item> + <p> + The timer created using <c>dist_util:start_timer/1</c>. + </p> + </item> + + <tag><marker id="hs_data_allowed"/><c>allowed</c></tag> + <item> + <p>Information passed as <c>Allowed</c> to + <c>accept_connection/5</c>. This field is only + mandatory when the remote node initiated the + connection. That is, when the connection is set + up via + <seealso marker="#accept_connection"><c>accept_connection/5</c></seealso>. + </p> + </item> + + <tag><marker id="hs_data_f_send"/><c>f_send</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrlr, Data) -> ok | {error, Error}]]></code> + <p> + where <c>DistCtrlr</c> is the identifier of + the distribution controller and <c>Data</c> + is io data to pass to the other side. + </p> + <p>Only used during handshake phase.</p> + </item> + + <tag><marker id="hs_data_f_recv"/><c>f_recv</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrlr, Length) -> {ok, Packet} | {error, Reason}]]></code> + <p> + where <c>DistCtrlr</c> is the identifier of the distribution + controller. + If <c>Length</c> is <c>0</c>, all available bytes should be + returned. If <c>Length > 0</c>, exactly <c>Length</c> bytes + should be returned, or an error; possibly discarding less + than <c>Length</c> bytes of data when the connection is + closed from the other side. + It is used for passive receive of data from the + other end. + </p> + <p>Only used during handshake phase.</p> + </item> + + <tag><marker id="hs_data_f_setopts_pre_nodeup"/><c>f_setopts_pre_nodeup</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrlr) -> ok | {error, Error}]]></code> + <p> + where <c>DistCtrlr</c> is the identifier of + the distribution controller. Called just + before the distribution channel is taken up + for normal traffic. + </p> + <p>Only used during handshake phase.</p> + </item> + + <tag><marker id="hs_data_f_setopts_post_nodeup"/><c>f_setopts_post_nodeup</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrlr) -> ok | {error, Error}]]></code> + <p> + where <c>DistCtrlr</c> is the identifier of + the distribution controller. Called just + after distribution channel has been taken + up for normal traffic. + </p> + <p>Only used during handshake phase.</p> + </item> + + <tag><marker id="hs_data_f_getll"/><c>f_getll</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrlr) -> ID]]></code> + <p> + where <c>DistCtrlr</c> is the identifier of + the distribution controller and <c>ID</c> is + the identifier of the low level entity that + handles the connection (often <c>DistCtrlr</c> + itself). + </p> + <p>Only used during handshake phase.</p> + </item> + + <tag><marker id="hs_data_f_address"/><c>f_address</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrlr, Node) -> NetAddress]]></code> + <p> + where <c>DistCtrlr</c> is the identifier of + the distribution controller, <c>Node</c> + is the node name of the node on the other end, + and <c>NetAddress</c> is a <c>#net_address{}</c> + record with information about the address + for the <c>Node</c> on the other end of the + connection. The <c>#net_address{}</c> record + is defined in + <c>kernel/include/net_address.hrl</c>. + </p> + <p>Only used during handshake phase.</p> + </item> + + <tag><marker id="hs_data_mf_tick"/><c>mf_tick</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrlr) -> void()]]></code> + <p> + where <c>DistCtrlr</c> is the identifier + of the distribution controller. This + function should send information over + the connection that is not interpreted + by the other end while increasing the + statistics of received packets on the + other end. This is usually implemented by + sending an empty packet. + </p> + <note><p> + It is of vital importance that this operation + does not block the caller for a long time. + This since it is called from the connection + supervisor. + </p></note> + <p>Used when connection is up.</p> + </item> + + <tag><marker id="hs_data_mf_getstat"/><c>mf_getstat</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrlr) -> {ok, Received, Sent, PendSend}]]></code> + <p> + where <c>DistCtrlr</c> is the identifier + of the distribution controller, <c>Received</c> + is received packets, <c>Sent</c> is + sent packets, and <c>PendSend</c> is + amount of packets in queue to be sent + or a <c>boolean()</c> indicating whether + there are packets in queue to be sent. + </p> + <note><p> + It is of vital importance that this operation + does not block the caller for a long time. + This since it is called from the connection + supervisor. + </p></note> + <p>Used when connection is up.</p> + </item> + + <tag><marker id="hs_data_request_type"/><c>request_type</c></tag> + <item> + <p> + The request <c>Type</c> as passed to + <seealso marker="#setup"><c>setup/5</c></seealso>. + This is only mandatory when the connection has + been initiated by this node. That is, the connection + is set up via <c>setup/5</c>. + </p> + </item> + + <tag><marker id="hs_data_mf_setopts"/><c>mf_setopts</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrl, Opts) -> ok | {error, Error}]]></code> + <p> + where <c>DistCtrlr</c> is the identifier + of the distribution controller and <c>Opts</c> + is a list of options to set on the connection. + </p> + <p>This function is optional. Used when connection is up.</p> + </item> + + <tag><marker id="hs_data_mf_getopts"/><c>mf_getopts</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrl, Opts) -> {ok, OptionValues} | {error, Error}]]></code> + <p> + where <c>DistCtrlr</c> is the identifier + of the distribution controller and <c>Opts</c> + is a list of options to read for the connection. + </p> + <p>This function is optional. Used when connection is up.</p> + </item> + + <tag><marker id="hs_data_f_handshake_complete"/><c>f_handshake_complete</c></tag> + <item> + <p> + A fun with the following signature: + </p> + <code type="none"><![CDATA[fun (DistCtrlr, Node, DHandle) -> void()]]></code> + <p> + where <c>DistCtrlr</c> is the identifier + of the distribution controller, <c>Node</c> is + the node name of the node connected at the other + end, and <c>DHandle</c> is a distribution handle + needed by a distribution controller process when + calling the following BIFs: + </p> + <list> + <item><p><seealso marker="erts:erlang#dist_ctrl_get_data/1"><c>erlang:dist_ctrl_get_data/1</c></seealso></p></item> + <item><p><seealso marker="erts:erlang#dist_ctrl_get_data_notification/1"><c>erlang:dist_ctrl_get_data_notification/1</c></seealso></p></item> + <item><p><seealso marker="erts:erlang#dist_ctrl_input_handler/2"><c>erlang:dist_ctrl_input_handler/2</c></seealso></p></item> + <item><p><seealso marker="erts:erlang#dist_ctrl_put_data/2"><c>erlang:dist_ctrl_put_data/2</c></seealso></p></item> + </list> + <p> + This function is called when the handshake has + completed and the distribution channel is up. + The distribution controller can begin dispatching + traffic over the channel. This function is optional. + </p> + <p>Only used during handshake phase.</p> + </item> + + <tag><marker id="hs_data_add_flags"/><c>add_flags</c></tag> + <item> + <p> + <seealso marker="erl_dist_protocol#dflags">Distribution flags</seealso> + to add to the connection. Currently all (non obsolete) flags will + automatically be enabled. + </p> + <p> + This flag field is optional. + </p> + </item> + + <tag><marker id="hs_data_reject_flags"/><c>reject_flags</c></tag> + <item> + <p> + <seealso marker="erl_dist_protocol#dflags">Distribution flags</seealso> + to reject. Currently the following distribution flags can be rejected: + </p> + <taglist> + <tag><c>DFLAG_DIST_HDR_ATOM_CACHE</c></tag> + <item>Do not use atom cache over this connection.</item> + <tag><c>DFLAGS_STRICT_ORDER_DELIVERY</c></tag> + <item>Do not use any features that require strict + order delivery.</item> + </taglist> + <p> + This flag field is optional. + </p> + </item> + + <tag><marker id="hs_data_require_flags"/><c>require_flags</c></tag> + <item> + <p> + Require these <seealso marker="erl_dist_protocol#dflags">distribution + flags</seealso> to be used. The connection will be aborted during the + handshake if the other end does not use them. + </p> + <p> + This flag field is optional. + </p> + </item> + + </taglist> + </section> + + <section> + <marker id="distribution_data_delivery"/> + <title>Distribution Data Delivery</title> + <p> + When using the default configuration, the data to pass + over a connection needs to be delivered as is + to the node on the receiving end in the <em>exact same + order</em>, with no loss of data what so ever, as sent + from the sending node. + </p> + <p> + The data delivery order can be relaxed by disabling + features that require strict ordering. This is done by + passing the <c>?DFLAGS_STRICT_ORDER_DELIVERY</c> + <seealso marker="erl_dist_protocol#dflags">distribution + flags</seealso> in the + <seealso marker="alt_dist#hs_data_reject_flags"><c>reject_flags</c></seealso> + field of the <seealso marker="#hs_data_record"><c>#hs_data{}</c></seealso> + record used when setting up the connection. When relaxed + ordering is used, only the order of signals with the same + sender/receiver pair has to be preserved. + However, note that disabling the features that require + strict ordering may have a negative impact on performance, + throughput, and/or latency. + </p> + </section> + + <section> + <marker id="enable_your_distribution_module"/> + <title>Enable Your Distribution Module</title> + + <p>For <c>net_kernel</c> to find out which distribution module to use, + the <c>erl</c> command-line argument <c>-proto_dist</c> is used. It + is followed by one or more distribution module names, with suffix + "_dist" removed. That is, <c>gen_tcp_dist</c> as a distribution module + is specified as <c>-proto_dist gen_tcp</c>.</p> + + <p>If no <c>epmd</c> (TCP port mapper daemon) is used, also command-line + option <c>-no_epmd</c> is to be specified, which makes + Erlang skip the <c>epmd</c> startup, both as an OS process and as an + Erlang ditto.</p> + </section> + + </section> + + <section> <title>The Driver</title> + + <note> + <p>This section was written a long time ago. Most of it is still + valid, but some things have changed since then. Some updates have + been made to the documentation of the driver presented here, + but more can be done and is planned for the future. + The reader is encouraged to read the + <seealso marker="erl_driver"><c>erl_driver</c></seealso> and + <seealso marker="driver_entry"><c>driver_entry</c></seealso> + documentation also.</p> + </note> + <p>Although Erlang drivers in general can be beyond the scope of this section, a brief introduction seems to be in place.</p> diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index 638e88ca31..71fe08d4e6 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -538,20 +538,6 @@ <p>Note that a distributed node will fail to start if epmd is not running.</p> </item> - <tag><marker id="smp"/><c><![CDATA[-smp [enable|auto|disable]]]></c></tag> - <item> - <p><c>-smp enable</c> and <c>-smp</c> start the Erlang runtime - system with SMP support enabled. This can fail if no runtime - system with SMP support is available. <c>-smp auto</c> starts - the Erlang runtime system with SMP support enabled if it is - available and more than one logical processor is detected. - <c>-smp disable</c> starts a runtime system without SMP support. - The runtime system without SMP support is deprecated and will - be removed in a future major release.</p> - <note> - <p>See also flag<seealso marker="#+S"><c>+S</c></seealso>.</p> - </note> - </item> <tag><c><![CDATA[-version]]></c> (emulator flag)</tag> <item> <p>Makes the emulator print its version number. The same @@ -902,7 +888,7 @@ <c><![CDATA[+S Schedulers:SchedulerOnline]]></c></tag> <item> <p>Sets the number of scheduler threads to create and scheduler threads - to set online when SMP support has been enabled. The maximum for both + to set online. The maximum for both values is 1024. If the Erlang runtime system is able to determine the number of logical processors configured and logical processors available, <c>Schedulers</c> defaults to logical processors @@ -920,8 +906,6 @@ <p>Specifying value <c>0</c> for <c>Schedulers</c> or <c>SchedulersOnline</c> resets the number of scheduler threads or scheduler threads online, respectively, to its default value.</p> - <p>This option is ignored if the emulator does not have SMP support - enabled (see flag <seealso marker="#smp"><c>-smp</c></seealso>).</p> </item> <tag><marker id="+SP"/><c><![CDATA[+SP SchedulersPercentage:SchedulersOnlinePercentage]]></c></tag> @@ -929,8 +913,8 @@ <p>Similar to <seealso marker="#+S"><c>+S</c></seealso> but uses percentages to set the number of scheduler threads to create, based on logical processors configured, and scheduler threads to set online, - based on logical processors available, when SMP support has been - enabled. Specified values must be > 0. For example, + based on logical processors available. + Specified values must be > 0. For example, <c>+SP 50:25</c> sets the number of scheduler threads to 50% of the logical processors configured, and the number of scheduler threads online to 25% of the logical processors available. @@ -945,15 +929,13 @@ and 8 logical cores available, the combination of the options <c>+S 4:4 +SP 50:25</c> (in either order) results in 2 scheduler threads (50% of 4) and 1 scheduler thread online (25% of 4).</p> - <p>This option is ignored if the emulator does not have SMP support - enabled (see flag <seealso marker="#smp"><c>-smp</c></seealso>).</p> </item> <tag><marker id="+SDcpu"/><c><![CDATA[+SDcpu DirtyCPUSchedulers:DirtyCPUSchedulersOnline]]></c></tag> <item> <p>Sets the number of dirty CPU scheduler threads to create and dirty - CPU scheduler threads to set online when threading support has been - enabled. The maximum for both values is 1024, and each value is + CPU scheduler threads to set online. + The maximum for both values is 1024, and each value is further limited by the settings for normal schedulers:</p> <list type="bulleted"> <item>The number of dirty CPU scheduler threads created cannot exceed @@ -977,16 +959,14 @@ executing on ordinary schedulers. If the amount of dirty CPU schedulers was allowed to be unlimited, dirty CPU bound jobs would potentially starve normal jobs.</p> - <p>This option is ignored if the emulator does not have threading - support enabled.</p> </item> <tag><marker id="+SDPcpu"/><c><![CDATA[+SDPcpu DirtyCPUSchedulersPercentage:DirtyCPUSchedulersOnlinePercentage]]></c></tag> <item> <p>Similar to <seealso marker="#+SDcpu"><c>+SDcpu</c></seealso> but uses percentages to set the number of dirty CPU scheduler threads to - create and the number of dirty CPU scheduler threads to set online - when threading support has been enabled. Specified values must be + create and the number of dirty CPU scheduler threads to set online. + Specified values must be > 0. For example, <c>+SDPcpu 50:25</c> sets the number of dirty CPU scheduler threads to 50% of the logical processors configured and the number of dirty CPU scheduler threads online to 25% of the @@ -1003,13 +983,11 @@ the combination of the options <c>+SDcpu 4:4 +SDPcpu 50:25</c> (in either order) results in 2 dirty CPU scheduler threads (50% of 4) and 1 dirty CPU scheduler thread online (25% of 4).</p> - <p>This option is ignored if the emulator does not have threading - support enabled.</p> </item> <tag><marker id="+SDio"/><c><![CDATA[+SDio DirtyIOSchedulers]]></c></tag> <item> - <p>Sets the number of dirty I/O scheduler threads to create when - threading support has been enabled. Valid range is 0-1024. By + <p>Sets the number of dirty I/O scheduler threads to create. + Valid range is 0-1024. By default, the number of dirty I/O scheduler threads created is 10, same as the default number of threads in the <seealso marker="#async_thread_pool_size">async thread pool</seealso>.</p> @@ -1019,8 +997,6 @@ expected to execute on dirty I/O schedulers. If the user should schedule CPU bound jobs on dirty I/O schedulers, these jobs might starve ordinary jobs executing on ordinary schedulers.</p> - <p>This option is ignored if the emulator does not have threading - support enabled.</p> </item> <tag><c><![CDATA[+sFlag Value]]></c></tag> <item> diff --git a/erts/doc/src/erl_dist_protocol.xml b/erts/doc/src/erl_dist_protocol.xml index 610351db6c..a78b13aaa4 100644 --- a/erts/doc/src/erl_dist_protocol.xml +++ b/erts/doc/src/erl_dist_protocol.xml @@ -829,7 +829,31 @@ DiB == gen_digest(ChA, ICA)? <item> <p>The node understand UTF-8 encoded atoms.</p> </item> + <tag><c>-define(DFLAG_MAP_TAG, 16#20000).</c></tag> + <item> + <p>The node understand the map tag.</p> + </item> + <tag><c>-define(DFLAG_BIG_CREATION, 16#40000).</c></tag> + <item> + <p>The node understand big node creation.</p> + </item> + <tag><c>-define(DFLAG_SEND_SENDER, 16#80000).</c></tag> + <item> + <p> + Use the <c>SEND_SENDER</c> + <seealso marker="#control_message">control message</seealso> + instead of the <c>SEND</c> control message and use the + <c>SEND_SENDER_TT</c> control message instead + of the <c>SEND_TT</c> control message. + </p> + </item> </taglist> + <p> + There are also a collection of <c>DFLAG</c>s bitwise or:ed + together in the <c>DFLAGS_STRICT_ORDER_DELIVERY</c> macro. + These flags corresponds to features that require strict + ordering of data over distribution channels. + </p> </section> </section> @@ -922,6 +946,7 @@ DiB == gen_digest(ChA, ICA)? </item> </taglist> + <marker id="control_message"/> <p>The <c>ControlMessage</c> is a tuple, where the first element indicates which distributed operation it encodes:</p> @@ -1028,4 +1053,49 @@ DiB == gen_digest(ChA, ICA)? </item> </taglist> </section> + + <section> + <title>New Ctrlmessages for Erlang/OTP 21</title> + <taglist> + <tag><c>SEND_SENDER</c></tag> + <item> + <p><c>{22, FromPid, ToPid}</c></p> + <p>Followed by <c>Message</c>.</p> + <p> + This control messages replace the <c>SEND</c> control + message and will be sent when the distribution flag + <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_SEND_SENDER</c></seealso> + has been negotiated in the connection setup handshake. + </p> + <note><p> + Messages encoded before the connection has + been set up may still use the <c>SEND</c> control + message. However, once a <c>SEND_SENDER</c> or <c>SEND_SENDER_TT</c> + control message has been sent, no more <c>SEND</c> + control messages will be sent in the same direction + on the connection. + </p></note> + </item> + <tag><c>SEND_SENDER_TT</c></tag> + <item> + <p><c>{23, FromPid, ToPid, TraceToken}</c></p> + <p>Followed by <c>Message</c>.</p> + <p> + This control messages replace the <c>SEND_TT</c> control + message and will be sent when the distribution flag + <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_SEND_SENDER</c></seealso> + has been negotiated in the connection setup handshake. + </p> + <note><p> + Messages encoded before the connection has + been set up may still use the <c>SEND_TT</c> control + message. However, once a <c>SEND_SENDER</c> or <c>SEND_SENDER_TT</c> + control message has been sent, no more <c>SEND_TT</c> + control messages will be sent in the same direction + on the connection. + </p></note> + </item> + </taglist> + </section> + </chapter> diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml index 5a69bed34c..419e41693e 100644 --- a/erts/doc/src/erl_nif.xml +++ b/erts/doc/src/erl_nif.xml @@ -206,7 +206,7 @@ ok <seealso marker="#enif_make_resource"> <c>enif_make_resource</c></seealso>. The term returned by <c>enif_make_resource</c> is opaque in nature. - It can be stored and passed between processes on the same node, but + It can be stored and passed between processes, but the only real end usage is to pass it back as an argument to a NIF. The NIF can then call <seealso marker="#enif_get_resource"> <c>enif_get_resource</c></seealso> and get back a pointer to the @@ -344,6 +344,81 @@ return term;</code> <c>enif_convert_time_unit()</c></seealso></item> </list> </item> + <tag><marker id="enif_ioq"/>I/O Queues</tag> + <item> + <p>The Erlang nif library contains function for easily working + with I/O vectors as used by the unix system call <c>writev</c>. + The I/O Queue is not thread safe, so some other synchronization + mechanism has to be used.</p> + <list type="bulleted"> + <item><seealso marker="#SysIOVec"> + <c>SysIOVec</c></seealso></item> + <item><seealso marker="#ErlNifIOVec"> + <c>ErlNifIOVec</c></seealso></item> + <item><seealso marker="#enif_ioq_create"> + <c>enif_ioq_create()</c></seealso></item> + <item><seealso marker="#enif_ioq_destroy"> + <c>enif_ioq_destroy()</c></seealso></item> + <item><seealso marker="#enif_ioq_enq_binary"> + <c>enif_ioq_enq_binary()</c></seealso></item> + <item><seealso marker="#enif_ioq_enqv"> + <c>enif_ioq_enqv()</c></seealso></item> + <item><seealso marker="#enif_ioq_deq"> + <c>enif_ioq_deq()</c></seealso></item> + <item><seealso marker="#enif_ioq_peek"> + <c>enif_ioq_peek()</c></seealso></item> + <item><seealso marker="#enif_inspect_iovec"> + <c>enif_inspect_iovec()</c></seealso></item> + <item><seealso marker="#enif_free_iovec"> + <c>enif_free_iovec()</c></seealso></item> + </list> + <p>Typical usage when writing to a file descriptor looks like this:</p> + <code type="none"><![CDATA[ +int writeiovec(ErlNifEnv *env, ERL_NIF_TERM term, ERL_NIF_TERM *tail, + ErlNifIOQueue *q, int fd) { + + ErlNifIOVec vec, *iovec = &vec; + SysIOVec *sysiovec; + int saved_errno; + int iovcnt, n; + + if (!enif_inspect_iovec(env, 64, term, tail, &iovec)) + return -2; + + if (enif_ioq_size(q) > 0) { + /* If the I/O queue contains data we enqueue the iovec and + then peek the data to write out of the queue. */ + if (!enif_ioq_enqv(q, iovec, 0)) + return -3; + + sysiovec = enif_ioq_peek(q, &iovcnt); + } else { + /* If the I/O queue is empty we skip the trip through it. */ + iovcnt = iovec->iovcnt; + sysiovec = iovec->iov; + } + + /* Attempt to write the data */ + n = writev(fd, sysiovec, iovcnt); + saved_errno = errno; + + if (enif_ioq_size(q) == 0) { + /* If the I/O queue was initially empty we enqueue any + remaining data into the queue for writing later. */ + if (n >= 0 && !enif_ioq_enqv(q, iovec, n)) + return -3; + } else { + /* Dequeue any data that was written from the queue. */ + if (n > 0 && !enif_ioq_deq(q, n, NULL)) + return -4; + } + + /* return n, which is either number of bytes written or -1 if + some error happened */ + errno = saved_errno; + return n; +}]]></code> + </item> <tag><marker id="lengthy_work"/>Long-running NIFs</tag> <item> <p>As mentioned in the <seealso marker="#WARNING">warning</seealso> text @@ -837,6 +912,36 @@ typedef enum { </item> </taglist> </item> + <tag><marker id="SysIOVec"/><c>SysIOVec</c></tag> + <item> + <p>A system I/O vector, as used by <c>writev</c> on + Unix and <c>WSASend</c> on Win32. It is used in + <c>ErlNifIOVec</c> and by + <seealso marker="#enif_ioq_peek"><c>enif_ioq_peek</c></seealso>.</p> + </item> + <tag><marker id="ErlNifIOVec"/><c>ErlNifIOVec</c></tag> + <item> + <code type="none"> +typedef struct { + int iovcnt; + size_t size; + SysIOVec* iov; +} ErlNifIOVec;</code> + <p>An I/O vector containing <c>iovcnt</c> <c>SysIOVec</c>s + pointing to the data. It is used by + <seealso marker="#enif_inspect_iovec"> + <c>enif_inspect_iovec</c></seealso> and + <seealso marker="#enif_ioq_enqv"> + <c>enif_ioq_enqv</c></seealso>.</p> + </item> + <tag><marker id="ErlNifIOQueueOpts"/><c>ErlNifIOQueueOpts</c></tag> + <item> + Options to configure a <c>ErlNifIOQueue</c>. + <taglist> + <tag>ERL_NIF_IOQ_NORMAL</tag> + <item><p>Create a normal I/O Queue</p></item> + </taglist> + </item> </taglist> </section> @@ -1143,6 +1248,31 @@ typedef enum { </func> <func> + <name><ret>void</ret> + <nametext>enif_free_iovec(ErlNifIOvec* iov)</nametext></name> + <fsummary>Free an ErlIOVec</fsummary> + <desc> + <p>Frees an io vector returned from + <seealso marker="#enif_inspect_iovec"> + <c>enif_inspect_iovec</c></seealso>. + This is needed only if a <c>NULL</c> environment is passed to + <seealso marker="#enif_inspect_iovec"> + <c>enif_inspect_iovec</c></seealso>.</p> + <code type="none"><![CDATA[ +ErlNifIOVec *iovec = NULL; +size_t max_elements = 128; +ERL_NIF_TERM tail; +if (!enif_inspect_iovec(NULL, max_elements, term, &tail, iovec)) + return 0; + +// Do things with the iovec + +/* Free the iovector, possibly in another thread or nif function call */ +enif_free_iovec(iovec);]]></code> + </desc> + </func> + + <func> <name><ret>int</ret><nametext>enif_get_atom(ErlNifEnv* env, ERL_NIF_TERM term, char* buf, unsigned size, ErlNifCharEncoding encode)</nametext> </name> @@ -1449,6 +1579,127 @@ typedef enum { </func> <func> + <name><ret>int</ret><nametext>enif_inspect_iovec(ErlNifEnv* + env, size_t max_elements, ERL_NIF_TERM iovec_term, ERL_NIF_TERM* tail, + ErlNifIOVec** iovec)</nametext></name> + <fsummary>Inspect a list of binaries as an ErlNifIOVec.</fsummary> + <desc> + <p>Fills <c>iovec</c> with the list of binaries provided in + <c>iovec_term</c>. The number of elements handled in the call is + limited to <c>max_elements</c>, and <c>tail</c> is set to the + remainder of the list. Note that the output may be longer than + <c>max_elements</c> on some platforms. + </p> + <p>To create a list of binaries from an arbitrary iolist, use + <seealso marker="erts:erlang#iolist_to_iovec/1"> + <c>erlang:iolist_to_iovec/1</c></seealso>.</p> + <p>When calling this function, <c>iovec</c> should contain a pointer to + <c>NULL</c> or a ErlNifIOVec structure that should be used if + possible. e.g. + </p> + <code type="none"> +/* Don't use a pre-allocated structure */ +ErlNifIOVec *iovec = NULL; +enif_inspect_iovec(env, max_elements, term, &tail, &iovec); + +/* Use a stack-allocated vector as an optimization for vectors with few elements */ +ErlNifIOVec vec, *iovec = &vec; +enif_inspect_iovec(env, max_elements, term, &tail, &iovec); +</code> + <p>The contents of the <c>iovec</c> is valid until the called nif + function returns. If the <c>iovec</c> should be valid after the nif + call returns, it is possible to call this function with a + <c>NULL</c> environment. If no environment is given the <c>iovec</c> + owns the data in the vector and it has to be explicitly freed using + <seealso marker="#enif_free_iovec"><c>enif_free_iovec</c> + </seealso>.</p> + <p>Returns <c>true</c> on success, or <c>false</c> if <c>iovec_term</c> + not an iovec.</p> + </desc> + </func> + + <func> + <name><ret>ErlNifIOQueue *</ret> + <nametext>enif_ioq_create(ErlNifIOQueueOpts opts)</nametext></name> + <fsummary>Create a new IO Queue</fsummary> + <desc> + <p>Create a new I/O Queue that can be used to store data. + <c>opts</c> has to be set to <c>ERL_NIF_IOQ_NORMAL</c>. + </p> + </desc> + </func> + + <func> + <name><ret>void</ret> + <nametext>enif_ioq_destroy(ErlNifIOQueue *q)</nametext></name> + <fsummary>Destroy an IO Queue and free it's content</fsummary> + <desc> + <p>Destroy the I/O queue and free all of it's contents</p> + </desc> + </func> + + <func> + <name><ret>int</ret> + <nametext>enif_ioq_deq(ErlNifIOQueue *q, size_t count, size_t *size)</nametext></name> + <fsummary>Dequeue count bytes from the IO Queue</fsummary> + <desc> + <p>Dequeue <c>count</c> bytes from the I/O queue. + If <c>size</c> is not <c>NULL</c>, the new size of the queue + is placed there.</p> + <p>Returns <c>true</c> on success, or <c>false</c> if the I/O does + not contain <c>count</c> bytes. On failure the queue is left un-altered.</p> + </desc> + </func> + + <func> + <name><ret>int</ret> + <nametext>enif_ioq_enq_binary(ErlNifIOQueue *q, ErlNifBinary *bin, size_t skip)</nametext></name> + <fsummary>Enqueue the binary into the IO Queue</fsummary> + <desc> + <p>Enqueue the <c>bin</c> into <c>q</c> skipping the first <c>skip</c> bytes.</p> + <p>Returns <c>true</c> on success, or <c>false</c> if <c>skip</c> is greater + than the size of <c>bin</c>. Any ownership of the binary data is transferred + to the queue and <c>bin</c> is to be considered read-only for the rest of the NIF + call and then as released.</p> + </desc> + </func> + + <func> + <name><ret>int</ret> + <nametext>enif_ioq_enqv(ErlNifIOQueue *q, ErlNifIOVec *iovec, size_t skip)</nametext></name> + <fsummary>Enqueue the iovec into the IO Queue</fsummary> + <desc> + <p>Enqueue the <c>iovec</c> into <c>q</c> skipping the first <c>skip</c> bytes.</p> + <p>Returns <c>true</c> on success, or <c>false</c> if <c>skip</c> is greater + than the size of <c>iovec</c>.</p> + </desc> + </func> + + <func> + <name><ret>SysIOVec *</ret> + <nametext>enif_ioq_peek(ErlNifIOQueue *q, int *iovlen)</nametext></name> + <fsummary>Peek inside the IO Queue</fsummary> + <desc> + <p>Get the I/O queue as a pointer to an array of <c>SysIOVec</c>s. + It also returns the number of elements in <c>iovlen</c>. + This is the only way to get data out of the queue.</p> + <p>Nothing is removed from the queue by this function, that must be done + with <seealso marker="#enif_ioq_deq"><c>enif_ioq_deq</c></seealso>.</p> + <p>The returned array is suitable to use with the Unix system + call <c>writev</c>.</p> + </desc> + </func> + + <func> + <name><ret>size_t</ret> + <nametext>enif_ioq_size(ErlNifIOQueue *q)</nametext></name> + <fsummary>Get the current size of the IO Queue</fsummary> + <desc> + <p>Get the size of <c>q</c>.</p> + </desc> + </func> + + <func> <name><ret>int</ret> <nametext>enif_is_atom(ErlNifEnv* env, ERL_NIF_TERM term)</nametext> </name> @@ -1952,10 +2203,33 @@ typedef enum { details, see the <seealso marker="#enif_resource_example">example of creating and returning a resource object</seealso> in the User's Guide.</p> - <p>Notice that the only defined behavior of using a resource term in - an Erlang program is to store it and send it between processes on the - same node. Other operations, such as matching or - <c>term_to_binary</c>, have unpredictable (but harmless) results.</p> + <note> + <p>Since ERTS 9.0 (OTP-20.0), resource terms have a defined behavior + when compared and serialized through <c>term_to_binary</c> or passed + between nodes.</p> + <list type="bulleted"> + <item> + <p>Two resource terms will compare equal iff they + would yield the same resource object pointer when passed to + <seealso marker="#enif_get_resource"><c>enif_get_resource</c></seealso>.</p> + </item> + <item> + <p>A resoure term can be serialized with <c>term_to_binary</c> and later + be fully recreated if the resource object is still alive when + <c>binary_to_term</c> is called. A <em>stale</em> resource term will be + returned from <c>binary_to_term</c> if the resource object has + been deallocated. <seealso marker="#enif_get_resource"><c>enif_get_resource</c></seealso> + will return false for stale resource terms.</p> + <p>The same principles of serialization apply when passing + resource terms in messages to remote nodes and back again. A + resource term will act stale on all nodes except the node where + its resource object is still alive in memory.</p> + </item> + </list> + <p>Before ERTS 9.0 (OTP-20.0), all resource terms did + compare equal to each other and to empty binaries (<c><<>></c>). + If serialized, they would be recreated as plain empty binaries.</p> + </note> </desc> </func> diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index 105734d5b2..ca8ba044e7 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -60,6 +60,14 @@ </desc> </datatype> <datatype> + <name>iovec()</name> + <desc> + <p>A list of binaries. This datatype is useful to use + together with <seealso marker="erl_nif#enif_inspect_iovec"> + <c>enif_inspect_iovec</c></seealso>.</p> + </desc> + </datatype> + <datatype> <name name="message_queue_data"></name> <desc> <p>See <seealso marker="#process_flag_message_queue_data"> @@ -181,6 +189,14 @@ </taglist> </desc> </datatype> + + <datatype> + <name name="dist_handle"></name> + <desc> + <p>An opaque handle identifing a distribution channel.</p> + </desc> + </datatype> + </datatypes> <funcs> @@ -424,6 +440,16 @@ Z = erlang:adler32_combine(X,Y,iolist_size(Data2)).</code> <seealso marker="#binary_to_atom/2"><c>binary_to_atom/2</c></seealso>, but the atom must exist.</p> <p>Failure: <c>badarg</c> if the atom does not exist.</p> + <note> + <p>Note that the compiler may optimize away atoms. For + example, the compiler will rewrite + <c>atom_to_list(some_atom)</c> to <c>"some_atom"</c>. If + that expression is the only mention of the atom + <c>some_atom</c> in the containing module, the atom will not + be created when the module is loaded, and a subsequent call + to <c>binary_to_existing_atom(<<"some_atom">>, utf8)</c> + will fail.</p> + </note> </desc> </func> @@ -1215,6 +1241,141 @@ end</code> </func> <func> + <name name="dist_ctrl_get_data" arity="1"/> + <fsummary>Get distribution channel data to pass to another node.</fsummary> + <desc> + <p> + Get distribution channel data from the local node that is + to be passed to the remote node. The distribution channel + is identified by <c><anno>DHandle</anno></c>. If no data + is available, the atom <c>none</c> is returned. One + can request to be informed by a message when more + data is available by calling + <seealso marker="erlang#dist_ctrl_get_data_notification/1"><c>erlang:dist_ctrl_get_data_notification(DHandle)</c></seealso>. + </p> + <note><p> + Only the process registered as distribution + controller for the distribution channel identified by + <c><anno>DHandle</anno></c> is allowed to call this + function. + </p></note> + <p> + This function is used when implementing an alternative + distribution carrier using processes as distribution + controllers. <c><anno>DHandle</anno></c> is retrived + via the callback + <seealso marker="erts:alt_dist#hs_data_f_handshake_complete"><c>f_handshake_complete</c></seealso>. + More information can be found in the documentation of + <seealso marker="erts:alt_dist#distribution_module">ERTS + User's Guide ➜ How to implement an Alternative Carrier + for the Erlang Distribution ➜ Distribution Module</seealso>. + </p> + </desc> + </func> + + <func> + <name name="dist_ctrl_get_data_notification" arity="1"/> + <fsummary>Request notification about available outgoing distribution channel data.</fsummary> + <desc> + <p> + Request notification when more data is available to + fetch using + <seealso marker="erlang#dist_ctrl_get_data/1"><c>erlang:dist_ctrl_get_data(DHandle)</c></seealso> + for the distribution channel identified by + <c><anno>DHandle</anno></c>. When more data is present, + the caller will be sent the message <c>dist_data</c>. + Once a <c>dist_data</c> messages has been sent, no + more <c>dist_data</c> messages will be sent until + the <c>dist_ctrl_get_data_notification/1</c> function has been called + again. + </p> + <note><p> + Only the process registered as distribution + controller for the distribution channel identified by + <c><anno>DHandle</anno></c> is allowed to call this + function. + </p></note> + <p> + This function is used when implementing an alternative + distribution carrier using processes as distribution + controllers. <c><anno>DHandle</anno></c> is retrived + via the callback + <seealso marker="erts:alt_dist#hs_data_f_handshake_complete"><c>f_handshake_complete</c></seealso>. + More information can be found in the documentation of + <seealso marker="erts:alt_dist#distribution_module">ERTS + User's Guide ➜ How to implement an Alternative Carrier + for the Erlang Distribution ➜ Distribution Module</seealso>. + </p> + </desc> + </func> + + <func> + <name name="dist_ctrl_input_handler" arity="2"/> + <fsummary>Register distribution channel input handler process.</fsummary> + <desc> + <p> + Register an alternate input handler process for the + distribution channel identified by <c><anno>DHandle</anno></c>. + Once this function has been called, <c><anno>InputHandler</anno></c> + is the only process allowed to call + <seealso marker="erlang#dist_ctrl_put_data/2"><c>erlang:dist_ctrl_put_data(DHandle, Data)</c></seealso> + with the <c><anno>DHandle</anno></c> identifing this distribution + channel. + </p> + <note><p> + Only the process registered as distribution + controller for the distribution channel identified by + <c><anno>DHandle</anno></c> is allowed to call this + function. + </p></note> + <p> + This function is used when implementing an alternative + distribution carrier using processes as distribution + controllers. <c><anno>DHandle</anno></c> is retrived + via the callback + <seealso marker="erts:alt_dist#hs_data_f_handshake_complete"><c>f_handshake_complete</c></seealso>. + More information can be found in the documentation of + <seealso marker="erts:alt_dist#distribution_module">ERTS + User's Guide ➜ How to implement an Alternative Carrier + for the Erlang Distribution ➜ Distribution Module</seealso>. + </p> + </desc> + </func> + + <func> + <name name="dist_ctrl_put_data" arity="2"/> + <fsummary>Pass data into the VM from a distribution channel.</fsummary> + <desc> + <p> + Deliver distribution channel data from a remote node to the + local node. + </p> + <note><p> + Only the process registered as distribution + controller for the distribution channel identified by + <c><anno>DHandle</anno></c> is allowed to call this + function unless an alternate input handler process + has been registered using + <seealso marker="erlang#dist_ctrl_input_handler/2"><c>erlang:dist_ctrl_input_handler(DHandle, InputHandler)</c></seealso>. + If an alternate input handler has been registered, only + the registered input handler process is allowed to call + this function. + </p></note> + <p> + This function is used when implementing an alternative + distribution carrier using processes as distribution + controllers. <c><anno>DHandle</anno></c> is retrived + via the callback + <seealso marker="erts:alt_dist#hs_data_f_handshake_complete"><c>f_handshake_complete</c></seealso>. + More information can be found in the documentation of + <seealso marker="erts:alt_dist#distribution_module">ERTS + User's Guide ➜ How to implement an Alternative Carrier + for the Erlang Distribution ➜ Distribution Module</seealso>. + </p> + </desc> + </func> + + <func> <name name="element" arity="2"/> <fsummary>Return the Nth element of a tuple.</fsummary> <type_desc variable="N">1..tuple_size(<anno>Tuple</anno>)</type_desc> @@ -1943,23 +2104,26 @@ os_prompt%</pre> <item>The runtime system exits with integer value <c><anno>Status</anno></c> as status code to the calling environment (OS). + <note> + <p>On many platforms, the OS supports only status + codes 0-255. A too large status code is truncated by clearing + the high bits.</p> + </note> </item> <tag>string()</tag> <item>An Erlang crash dump is produced with <c><anno>Status</anno></c> as slogan. Then the runtime system exits with status code <c>1</c>. - Note that only code points in the range 0-255 may be used - and the string will be truncated if longer than 200 characters. + The string will be truncated if longer than 200 characters. + <note> + <p>Before ERTS 9.1 (OTP-20.1) only code points in the range 0-255 + was accepted in the string. Now any unicode string is valid.</p> + </note> </item> <tag><c>abort</c></tag> <item>The runtime system aborts producing a core dump, if that is enabled in the OS. </item> </taglist> - <note> - <p>On many platforms, the OS supports only status - codes 0-255. A too large status code is truncated by clearing - the high bits.</p> - </note> <p>For integer <c><anno>Status</anno></c>, the Erlang runtime system closes all ports and allows async threads to finish their operations before exiting. To exit without such flushing, use @@ -2125,6 +2289,15 @@ os_prompt%</pre> </func> <func> + <name name="iolist_to_iovec" arity="1"/> + <fsummary>Converts an iolist to a iovec.</fsummary> + <desc> + <p>Returns an iovec that is made from the integers and binaries in + <c><anno>IoListOrBinary</anno></c>.</p> + </desc> + </func> + + <func> <name name="is_alive" arity="0"/> <fsummary>Check whether the local node is alive.</fsummary> <desc> @@ -2458,6 +2631,15 @@ os_prompt%</pre> but only if there already exists such atom.</p> <p>Failure: <c>badarg</c> if there does not already exist an atom whose text representation is <c><anno>String</anno></c>.</p> + <note> + <p>Note that the compiler may optimize away atoms. For + example, the compiler will rewrite + <c>atom_to_list(some_atom)</c> to <c>"some_atom"</c>. If + that expression is the only mention of the atom + <c>some_atom</c> in the containing module, the atom will not + be created when the module is loaded, and a subsequent call + to <c>list_to_existing_atom("some_atom")</c> will fail.</p> + </note> </desc> </func> @@ -4284,7 +4466,6 @@ RealSystem = system + MissedSystem</code> <desc> <p><c><anno>Locking</anno></c> is one of the following:</p> <list type="bulleted"> - <item><c>false</c> (emulator without SMP support)</item> <item><c>port_level</c> (port-specific locking)</item> <item><c>driver_level</c> (driver-specific locking)</item> </list> @@ -4688,8 +4869,8 @@ RealSystem = system + MissedSystem</code> selected for execution. Notice however that this does <em>not</em> mean that no processes on priority <c>low</c> or <c>normal</c> can run when processes - are running on priority <c>high</c>. On the runtime - system with SMP support, more processes can be running + are running on priority <c>high</c>. When using multiple + schedulers, more processes can be running in parallel than processes on priority <c>high</c>. That is, a <c>low</c> and a <c>high</c> priority process can execute at the same time.</p> @@ -4704,10 +4885,8 @@ RealSystem = system + MissedSystem</code> execution.</p> <note> <p>Do not depend on the scheduling - to remain exactly as it is today. Scheduling, at least on - the runtime system with SMP support, is likely to be - changed in a future release to use available - processor cores better.</p> + to remain exactly as it is today. Scheduling is likely to be + changed in a future release to use available processor cores better.</p> </note> <p>There is <em>no</em> automatic mechanism for avoiding priority inversion, such as priority inheritance @@ -6219,8 +6398,7 @@ true</pre> <p><c>statistics(exact_reductions)</c> is a more expensive operation than <seealso marker="#statistics_reductions"> - statistics(reductions)</seealso>, - especially on an Erlang machine with SMP support.</p> + statistics(reductions)</seealso>.</p> </note> </desc> </func> @@ -6604,8 +6782,8 @@ ok than available logical processors, this value may be greater than <c>1.0</c>.</p> <p>As of ERTS version 9.0, the Erlang runtime system - with SMP support will as default have more schedulers - than logical processors. This due to the dirty schedulers.</p> + will as default have more schedulers than logical processors. + This due to the dirty schedulers.</p> <note> <p><c>scheduler_wall_time</c> is by default disabled. To enable it, use @@ -7975,9 +8153,7 @@ ok <taglist> <tag><c>disabled</c></tag> <item> - <p>The emulator has only one scheduler thread. The - emulator does not have SMP support, or have been - started with only one scheduler thread.</p> + <p>The emulator has been started with only one scheduler thread.</p> </item> <tag><c>blocked</c></tag> <item> @@ -8340,8 +8516,7 @@ ok </item> <tag><c>smp_support</c></tag> <item> - <p>Returns <c>true</c> if the emulator has been compiled - with SMP support, otherwise <c>false</c> is returned.</p> + <p>Returns <c>true</c>.</p> </item> <tag><marker id="system_info_start_time"/><c>start_time</c></tag> <item> @@ -8364,8 +8539,7 @@ ok </item> <tag><c>threads</c></tag> <item> - <p>Returns <c>true</c> if the emulator has been compiled - with thread support, otherwise <c>false</c> is returned.</p> + <p>Returns <c>true</c>.</p> </item> <tag><c>thread_pool_size</c></tag> <item> @@ -10484,9 +10658,9 @@ true</pre> <c>receive after 1 -> ok end</c>, except that <c>yield()</c> is faster.</p> <warning> - <p>There is seldom or never any need to use this BIF, - especially in the SMP emulator, as other processes have a - chance to run in another scheduler thread anyway. + <p>There is seldom or never any need to use this BIF + as other processes have a chance to run in another scheduler + thread anyway. Using this BIF without a thorough grasp of how the scheduler works can cause performance degradation.</p> </warning> diff --git a/erts/doc/src/notes.xml b/erts/doc/src/notes.xml index 722f7aaebd..10b963a4e8 100644 --- a/erts/doc/src/notes.xml +++ b/erts/doc/src/notes.xml @@ -31,6 +31,109 @@ </header> <p>This document describes the changes made to the ERTS application.</p> +<section><title>Erts 9.0.5</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p> + Fixed bug in <c>binary_to_term</c> and + <c>binary_to_atom</c> that could cause VM crash. + Typically happens when the last character of an UTF8 + string is in the range 128 to 255, but truncated to only + one byte. Bug exists in <c>binary_to_term</c> since ERTS + version 5.10.2 (OTP_R16B01) and <c>binary_to_atom</c> + since ERTS version 9.0 (OTP-20.0).</p> + <p> + Own Id: OTP-14590 Aux Id: ERL-474 </p> + </item> + </list> + </section> + +</section> + +<section><title>Erts 9.0.4</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p> + A timer internal bit-field used for storing scheduler id + was too small. As a result, VM internal timer data + structures could become inconsistent when using 1024 + schedulers on the system. Note that systems with less + than 1024 schedulers are not effected by this bug.</p> + <p> + This bug was introduced in ERTS version 7.0 (OTP 18.0).</p> + <p> + Own Id: OTP-14548 Aux Id: OTP-11997, ERL-468 </p> + </item> + <item> + <p> + Automatic cleanup of a BIF timer, when the owner process + terminated, could race with the timeout of the timer. + This could cause the VM internal data structures to + become inconsistent which very likely caused a VM crash.</p> + <p> + This bug was introduced in ERTS version 9.0 (OTP 20.0).</p> + <p> + Own Id: OTP-14554 Aux Id: OTP-14356, ERL-468 </p> + </item> + </list> + </section> + +</section> + +<section><title>Erts 9.0.3</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>Binary append operations did not check for overflow, + resulting in nonsensical results when huge binaries were + appended.</p> + <p> + Own Id: OTP-14524</p> + </item> + </list> + </section> + +</section> + +<section><title>Erts 9.0.2</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p> + Added missing release notes for OTP-14491 ("performance + bug in pre-allocators") which was included in erts-9.0.1 + (OTP-20.0.1).</p> + <p> + Own Id: OTP-14494</p> + </item> + <item> + <p>Fixed a bug that prevented TCP sockets from being + closed properly on send timeouts.</p> + <p> + Own Id: OTP-14509</p> + </item> + <item> + <p> + Fixed bug in operator <c>bxor</c> causing erroneuos + result when one operand is a big <em>negative</em> + integer with the lowest <c>N*W</c> bits as zero and the + other operand not larger than <c>N*W</c> bits. <c>N</c> + is an integer of 1 or larger and <c>W</c> is 32 or 64 + depending on word size.</p> + <p> + Own Id: OTP-14514</p> + </item> + </list> + </section> + +</section> + <section><title>Erts 9.0.1</title> <section><title>Fixed Bugs and Malfunctions</title> @@ -63,6 +166,17 @@ <p> Own Id: OTP-14484</p> </item> + <item> + <p> + Fix performance bug in pre-allocators that could cause + them to permanently fall back on normal more expensive memory + allocation. Pre-allocators are used for quick allocation + of short lived meta data used by messages and other + scheduled tasks. Bug exists since OTP_R15B02. + [this release note was missing in erts-9.0.1]</p> + <p> + Own Id: OTP-14491</p> + </item> </list> </section> @@ -510,7 +624,7 @@ marker="erts:erl"><c>erl</c></seealso> command.</p> <p> See <url - href="http://pcre.org/original/changelog.txt"><c>http://pcre.org/original/changelog.txt</c></url> + href="http://pcre.org/original/changelog.txt">http://pcre.org/original/changelog.txt</url> for information about changes made to PCRE between the versions 8.33 and 8.40.</p> <p> @@ -3448,8 +3562,7 @@ <p>The previously introduced "eager check I/O" feature is now enabled by default.</p> <p>Eager check I/O can be disabled using the <c>erl</c> - command line argument: <seealso - marker="erl#+secio"><c>+secio false</c></seealso></p> + command line argument: <c>+secio false</c></p> <p>Characteristics impact compared to previous default:</p> <list> <item>Lower latency and smoother management of externally triggered I/O operations.</item> @@ -4230,8 +4343,7 @@ prioritized to the same extent as when eager check I/O is disabled.</p> <p>Eager check I/O can be enabled using the <c>erl</c> - command line argument: <seealso - marker="erl#+secio"><c>+secio true</c></seealso></p> + command line argument: <c>+secio true</c></p> <p>Characteristics impact when enabled:</p> <list> <item>Lower latency and smoother management of externally triggered I/O operations.</item> <item>A slightly reduced diff --git a/erts/doc/src/zlib.xml b/erts/doc/src/zlib.xml index 1d272c4c18..f5cc1b1e64 100644 --- a/erts/doc/src/zlib.xml +++ b/erts/doc/src/zlib.xml @@ -65,13 +65,17 @@ list_to_binary([Compressed|Last])</pre> <tag><c>badarg</c></tag> <item>Bad argument. </item> + <tag><c>not_initialized</c></tag> + <item>The stream hasn't been initialized, eg. if + <seealso marker="#inflateInit/1"><c>inflateInit/1</c></seealso> wasn't + called prior to a call to + <seealso marker="#inflate/2"><c>inflate/2</c></seealso>. + </item> <tag><c>data_error</c></tag> <item>The data contains errors. </item> <tag><c>stream_error</c></tag> <item>Inconsistent stream state.</item> - <tag><c>einval</c></tag> - <item>Bad value or wrong function called.</item> <tag><c>{need_dictionary,Adler32}</c></tag> <item>See <seealso marker="#inflate/2"><c>inflate/2</c></seealso>. </item> @@ -90,6 +94,9 @@ list_to_binary([Compressed|Last])</pre> <name name="zlevel"/> </datatype> <datatype> + <name name="zflush"/> + </datatype> + <datatype> <name name="zmemlevel"/> </datatype> <datatype> @@ -112,6 +119,11 @@ list_to_binary([Compressed|Last])</pre> <fsummary>Calculate the Adler checksum.</fsummary> <desc> <p>Calculates the Adler-32 checksum for <c><anno>Data</anno></c>.</p> + <warning> + <p>This function is deprecated and will be removed in a future + release. Use <seealso marker="erts:erlang#adler32/1"> + <c>erlang:adler32/1</c></seealso> instead.</p> + </warning> </desc> </func> @@ -127,6 +139,11 @@ list_to_binary([Compressed|Last])</pre> Crc = lists:foldl(fun(Data,Crc0) -> zlib:adler32(Z, Crc0, Data), end, zlib:adler32(Z,<< >>), Datas)</pre> + <warning> + <p>This function is deprecated and will be removed in a future + release. Use <seealso marker="erts:erlang#adler32/2"> + <c>erlang:adler32/2</c></seealso> instead.</p> + </warning> </desc> </func> @@ -141,6 +158,11 @@ Crc = lists:foldl(fun(Data,Crc0) -> <p>This function returns the <c><anno>Adler</anno></c> checksum of <c>[Data1,Data2]</c>, requiring only <c><anno>Adler1</anno></c>, <c><anno>Adler2</anno></c>, and <c><anno>Size2</anno></c>.</p> + <warning> + <p>This function is deprecated and will be removed in a future + release. Use <seealso marker="erts:erlang#adler32_combine/3"> + <c>erlang:adler32_combine/3</c></seealso> instead.</p> + </warning> </desc> </func> @@ -165,6 +187,12 @@ Crc = lists:foldl(fun(Data,Crc0) -> <fsummary>Get current CRC.</fsummary> <desc> <p>Gets the current calculated CRC checksum.</p> + <warning> + <p>This function is deprecated and will be removed in a future + release. Use <seealso marker="erts:erlang#crc32/1"> + <c>erlang:crc32/1</c></seealso> on the uncompressed data + instead.</p> + </warning> </desc> </func> @@ -173,6 +201,11 @@ Crc = lists:foldl(fun(Data,Crc0) -> <fsummary>Calculate CRC.</fsummary> <desc> <p>Calculates the CRC checksum for <c><anno>Data</anno></c>.</p> + <warning> + <p>This function is deprecated and will be removed in a future + release. Use <seealso marker="erts:erlang#crc32/1"> + <c>erlang:crc32/1</c></seealso> instead.</p> + </warning> </desc> </func> @@ -188,6 +221,11 @@ Crc = lists:foldl(fun(Data,Crc0) -> Crc = lists:foldl(fun(Data,Crc0) -> zlib:crc32(Z, Crc0, Data), end, zlib:crc32(Z,<< >>), Datas)</pre> + <warning> + <p>This function is deprecated and will be removed in a future + release. Use <seealso marker="erts:erlang#crc32/2"> + <c>erlang:crc32/2</c></seealso> instead.</p> + </warning> </desc> </func> @@ -202,6 +240,11 @@ Crc = lists:foldl(fun(Data,Crc0) -> <p>This function returns the <c><anno>CRC</anno></c> checksum of <c>[Data1,Data2]</c>, requiring only <c><anno>CRC1</anno></c>, <c><anno>CRC2</anno></c>, and <c><anno>Size2</anno></c>.</p> + <warning> + <p>This function is deprecated and will be removed in a future + release. Use <seealso marker="erts:erlang#crc32_combine/3"> + <c>erlang:crc32_combine/3</c></seealso> instead.</p> + </warning> </desc> </func> @@ -407,8 +450,8 @@ list_to_binary([B1,B2])</pre> <seealso marker="#deflateInit/1"><c>deflateInit/1,2,6</c></seealso> or <seealso marker="#deflateReset/1"><c>deflateReset/1</c></seealso>, before any call of - <seealso marker="#deflate/3"><c>deflate/3</c></seealso>. - The compressor and decompressor must use the same dictionary (see + <seealso marker="#deflate/3"><c>deflate/3</c></seealso>.</p> + <p>The compressor and decompressor must use the same dictionary (see <seealso marker="#inflateSetDictionary/2"> <c>inflateSetDictionary/2</c></seealso>).</p> <p>The Adler checksum of the dictionary is returned.</p> @@ -420,6 +463,10 @@ list_to_binary([B1,B2])</pre> <fsummary>Get buffer size.</fsummary> <desc> <p>Gets the size of the intermediate buffer.</p> + <warning> + <p>This function is deprecated and will be removed in a future + release.</p> + </warning> </desc> </func> @@ -443,14 +490,31 @@ list_to_binary([B1,B2])</pre> <name name="inflate" arity="2"/> <fsummary>Decompress data.</fsummary> <desc> - <p>Decompresses as much data as possible. - It can introduce some output latency (reading - input without producing any output).</p> - <p>If a preset dictionary is needed at this point (see - <seealso marker="#inflateSetDictionary/2"> - <c>inflateSetDictionary/2</c></seealso>), <c>inflate/2</c> throws a - <c>{need_dictionary,Adler}</c> exception, where <c>Adler</c> is - the Adler-32 checksum of the dictionary chosen by the compressor.</p> + <p>Equivalent to + <seealso marker="#inflate/3"><c>inflate(Z, Data, [])</c></seealso> + </p> + </desc> + </func> + + <func> + <name name="inflate" arity="3"/> + <fsummary>Decompress data.</fsummary> + <desc> + <p>Decompresses as much data as possible. It can introduce some output + latency (reading input without producing any output).</p> + <p>Currently the only available option is + <c>{exception_on_need_dict,boolean()}</c> which controls whether the + function should throw an exception when a preset dictionary is + required for decompression. When set to false, a + <c>need_dictionary</c> tuple will be returned instead. See + <seealso marker="#inflateSetDictionary/2"> + <c>inflateSetDictionary/2</c></seealso> for details.</p> + <warning> + <p>This option defaults to <c>true</c> for backwards compatibility + but we intend to remove the exception behavior in a future + release. New code that needs to handle dictionaries manually + should always specify <c>{exception_on_need_dict,false}</c>.</p> + </warning> </desc> </func> @@ -458,6 +522,11 @@ list_to_binary([B1,B2])</pre> <name name="inflateChunk" arity="1"/> <fsummary>Read next uncompressed chunk.</fsummary> <desc> + <warning> + <p>This function is deprecated and will be removed in a future + release. Use <seealso marker="#safeInflate/2"><c>safeInflate/2</c> + </seealso> instead.</p> + </warning> <p>Reads the next chunk of uncompressed data, initialized by <seealso marker="#inflateChunk/2"><c>inflateChunk/2</c></seealso>.</p> <p>This function is to be repeatedly called, while it returns @@ -469,23 +538,27 @@ list_to_binary([B1,B2])</pre> <name name="inflateChunk" arity="2"/> <fsummary>Decompress data with limited output size.</fsummary> <desc> + <warning> + <p>This function is deprecated and will be removed in a future + release. Use <seealso marker="#safeInflate/2"><c>safeInflate/2</c> + </seealso> instead.</p> + </warning> <p>Like <seealso marker="#inflate/2"><c>inflate/2</c></seealso>, - but decompresses no more data than will fit in the buffer configured - through <seealso marker="#setBufSize/2"><c>setBufSize/2</c></seealso>. - Is is useful when decompressing a stream with a high compression - ratio, such that a small amount of compressed input can expand up to - 1000 times.</p> + but decompresses no more data than will fit in the buffer configured + through <seealso marker="#setBufSize/2"><c>setBufSize/2</c> + </seealso>. Is is useful when decompressing a stream with a high + compression ratio, such that a small amount of compressed input can + expand up to 1000 times.</p> <p>This function returns <c>{more, Decompressed}</c>, when there is - more output available, and - <seealso marker="#inflateChunk/1"><c>inflateChunk/1</c></seealso> - is to be used to read it.</p> - <p>This function can introduce some output latency (reading - input without producing any output).</p> - <p>If a preset dictionary is needed at this point (see - <seealso marker="#inflateSetDictionary/2"> - <c>inflateSetDictionary/2</c></seealso>), this function throws a - <c>{need_dictionary,Adler}</c> exception, where <c>Adler</c> is - the Adler-32 checksum of the dictionary chosen by the compressor.</p> + more output available, and + <seealso marker="#inflateChunk/1"><c>inflateChunk/1</c></seealso> + is to be used to read it.</p> + <p>This function can introduce some output latency (reading input + without producing any output).</p> + <p>An exception will be thrown if a preset dictionary is required for + further decompression. See + <seealso marker="#inflateSetDictionary/2"> + <c>inflateSetDictionary/2</c></seealso> for details.</p> <p>Example:</p> <pre> walk(Compressed, Handler) -> @@ -517,6 +590,18 @@ loop(Z, Handler, Uncompressed) -> </func> <func> + <name name="inflateGetDictionary" arity="1"/> + <fsummary>Return the decompression dictionary.</fsummary> + <desc> + <p>Returns the decompression dictionary currently in use + by the stream. This function must be called between + <seealso marker="#inflateInit/1"><c>inflateInit/1,2</c></seealso> + and <seealso marker="#inflateEnd/1"><c>inflateEnd</c></seealso>.</p> + <p>Only supported if ERTS was compiled with zlib >= 1.2.8.</p> + </desc> + </func> + + <func> <name name="inflateInit" arity="1"/> <fsummary>Initialize a session for decompression.</fsummary> <desc> @@ -562,45 +647,83 @@ loop(Z, Handler, Uncompressed) -> <fsummary>Initialize the decompression dictionary.</fsummary> <desc> <p>Initializes the decompression dictionary from the specified - uncompressed byte sequence. This function must be called - immediately after a call of - <seealso marker="#inflate/2"><c>inflate/2</c></seealso> - if this call threw a <c>{need_dictionary,Adler}</c> exception. - The dictionary chosen by the compressor can be determined from the - Adler value thrown by the call to <c>inflate/2</c>. - The compressor and decompressor must use the same dictionary (see - <seealso marker="#deflateSetDictionary/2"> - <c>deflateSetDictionary/2</c></seealso>).</p> + uncompressed byte sequence. This function must be called as a + response to an inflate operation (eg. + <seealso marker="#safeInflate/2"><c>safeInflate/2</c></seealso>) + returning <c>{need_dictionary,Adler,Output}</c> or in the case of + deprecated functions, throwing an + <c>{'EXIT',{{need_dictionary,Adler},_StackTrace}}</c> exception.</p> + <p>The dictionary chosen by the compressor can be determined from the + Adler value returned or thrown by the call to the inflate function. + The compressor and decompressor must use the same dictionary (See + <seealso marker="#deflateSetDictionary/2"> + <c>deflateSetDictionary/2</c></seealso>).</p> + <p>After setting the dictionary the inflate operation should be + retried without new input.</p> <p>Example:</p> <pre> -unpack(Z, Compressed, Dict) -> +deprecated_unpack(Z, Compressed, Dict) -> case catch zlib:inflate(Z, Compressed) of - {'EXIT',{{need_dictionary,DictID},_}} -> - zlib:inflateSetDictionary(Z, Dict), + {'EXIT',{{need_dictionary,_DictID},_}} -> + ok = zlib:inflateSetDictionary(Z, Dict), Uncompressed = zlib:inflate(Z, []); Uncompressed -> Uncompressed - end.</pre> + end. + +new_unpack(Z, Compressed, Dict) -> + case zlib:inflate(Z, Compressed, [{exception_on_need_dict, false}]) of + {need_dictionary, _DictId, Output} -> + ok = zlib:inflateSetDictionary(Z, Dict), + [Output | zlib:inflate(Z, [])]; + Uncompressed -> + Uncompressed + end.</pre> </desc> </func> <func> - <name name="inflateGetDictionary" arity="1"/> - <fsummary>Return the decompression dictionary.</fsummary> + <name name="open" arity="0"/> + <fsummary>Open a stream and return a stream reference.</fsummary> <desc> - <p>Returns the decompression dictionary currently in use - by the stream. This function must be called between - <seealso marker="#inflateInit/1"><c>inflateInit/1,2</c></seealso> - and <seealso marker="#inflateEnd/1"><c>inflateEnd</c></seealso>.</p> - <p>Only supported if ERTS was compiled with zlib >= 1.2.8.</p> + <p>Opens a zlib stream.</p> </desc> </func> <func> - <name name="open" arity="0"/> - <fsummary>Open a stream and return a stream reference.</fsummary> + <name name="safeInflate" arity="2"/> + <fsummary>Decompress data with limited output size.</fsummary> <desc> - <p>Opens a zlib stream.</p> + <p>Like <seealso marker="#inflate/2"><c>inflate/2</c></seealso>, + but returns once it has expanded beyond a small + implementation-defined threshold. It's useful when decompressing + untrusted input which could have been maliciously crafted to expand + until the system runs out of memory.</p> + <p>This function returns <c>{continue | finished, Output}</c>, where + <anno>Output</anno> is the data that was decompressed in this call. + New input can be queued up on each call if desired, and the function + will return <c>{finished, Output}</c> once all queued data has been + decompressed.</p> + <p>This function can introduce some output latency (reading + input without producing any output).</p> + <p>If a preset dictionary is required for further decompression, this + function returns a <c>need_dictionary</c> tuple. See + <seealso marker="#inflateSetDictionary/2"> + <c>inflateSetDictionary/2</c></seealso>) for details.</p> + <p>Example:</p> + <pre> +walk(Compressed, Handler) -> + Z = zlib:open(), + zlib:inflateInit(Z), + loop(Z, Handler, zlib:safeInflate(Z, Compressed)), + zlib:inflateEnd(Z), + zlib:close(Z). + +loop(Z, Handler, {continue, Output}) -> + Handler(Output), + loop(Z, Handler, zlib:safeInflate(Z, [])); +loop(Z, Handler, {finished, Output}) -> + Handler(Output).</pre> </desc> </func> @@ -609,6 +732,10 @@ unpack(Z, Compressed, Dict) -> <fsummary>Set buffer size.</fsummary> <desc> <p>Sets the intermediate buffer size.</p> + <warning> + <p>This function is deprecated and will be removed in a future + release.</p> + </warning> </desc> </func> |