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-rw-r--r--lib/erl_interface/doc/src/erl_connect.xml546
1 files changed, 318 insertions, 228 deletions
diff --git a/lib/erl_interface/doc/src/erl_connect.xml b/lib/erl_interface/doc/src/erl_connect.xml
index 0799e30905..a027cb0a84 100644
--- a/lib/erl_interface/doc/src/erl_connect.xml
+++ b/lib/erl_interface/doc/src/erl_connect.xml
@@ -28,27 +28,30 @@
<docno></docno>
<approved>Bjarne D&auml;cker</approved>
<checked>Torbj&ouml;rn T&ouml;rnkvist</checked>
- <date>980703</date>
+ <date>1998-07-03</date>
<rev>A</rev>
<file>erl_connect.xml</file>
</header>
<lib>erl_connect</lib>
- <libsummary>Communicate with Distributed Erlang</libsummary>
+ <libsummary>Communicate with distributed Erlang.</libsummary>
<description>
<p>This module provides support for communication between distributed
- Erlang nodes and C nodes, in a manner that is transparent to Erlang
+ Erlang nodes and C-nodes, in a manner that is transparent to Erlang
processes.</p>
- <p>A C node appears to Erlang as a
- <em>hidden node</em>.
+
+ <p>A C-node appears to Erlang as a <em>hidden node</em>.
That is, Erlang processes that know the name of the
- C node are able to communicate with it in a normal manner, but
- the node name will not appear in the listing provided by the
- Erlang function <c><![CDATA[nodes/0]]></c>.</p>
+ C-node can communicate with it in a normal manner, but
+ the node name does not appear in the listing provided by
+ <seealso marker="erts:erlang#nodes/0"><c>erlang:nodes/0</c></seealso>
+ in <c>ERTS</c>.</p>
</description>
+
<funcs>
<func>
<name><ret>int</ret><nametext>erl_accept(listensock, conp)</nametext></name>
<fsummary>Accept a connection.</fsummary>
+ <marker id="erl_accept"/>
<type>
<v>int listensock;</v>
<v>ErlConnect *conp;</v>
@@ -56,10 +59,12 @@
<desc>
<p>This function is used by a server process to accept a
connection from a client process.</p>
- <p><c><![CDATA[listensock]]></c> is an open socket descriptor on which
- <c><![CDATA[listen()]]></c> has previously been called.</p>
- <p><c><![CDATA[conp]]></c> is a pointer to an <c><![CDATA[ErlConnect]]></c> struct,
- described as follows:</p>
+ <list type="bulleted">
+ <item><c><![CDATA[listensock]]></c> is an open socket descriptor on
+ which <c><![CDATA[listen()]]></c> has previously been called.</item>
+ <item><c><![CDATA[conp]]></c> is a pointer to an
+ <c><![CDATA[ErlConnect]]></c> struct, described as follows:</item>
+ </list>
<code type="none"><![CDATA[
typedef struct {
char ipadr[4];
@@ -72,6 +77,7 @@ typedef struct {
<c><![CDATA[erl_errno]]></c> is set to <c><![CDATA[EIO]]></c>.</p>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_close_connection(fd)</nametext></name>
<fsummary>Close a connection to an Erlang node.</fsummary>
@@ -79,47 +85,54 @@ typedef struct {
<v>int fd;</v>
</type>
<desc>
- <p>This function closes an open connection to an Erlang node.</p>
+ <p>Closes an open connection to an Erlang node.</p>
<p><c><![CDATA[Fd]]></c> is a file descriptor obtained from
- <c><![CDATA[erl_connect()]]></c> or <c><![CDATA[erl_xconnect()]]></c>.</p>
- <p>On success, 0 is returned. If the call fails, a non-zero value
- is returned, and the reason for
- the error can be obtained with the appropriate platform-dependent
- call.</p>
+ <c><![CDATA[erl_connect()]]></c> or
+ <c><![CDATA[erl_xconnect()]]></c>.</p>
+ <p>Returns <c>0</c> on success. If the call fails, a non-zero value
+ is returned, and the reason for the error can be obtained with the
+ appropriate platform-dependent call.</p>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_connect(node)</nametext></name>
<name><ret>int</ret><nametext>erl_xconnect(addr, alive)</nametext></name>
- <fsummary>Establishe a connection to an Erlang node.</fsummary>
+ <fsummary>Establish a connection to an Erlang node.</fsummary>
<type>
<v>char *node, *alive;</v>
<v>struct in_addr *addr;</v>
</type>
<desc>
- <p>These functions set up a connection to an Erlang node.</p>
- <p><c><![CDATA[erl_xconnect()]]></c> requires the IP address of the remote
- host and the alive name of the remote node
- to be specified. <c><![CDATA[erl_connect()]]></c> provides an alternative
+ <p>Sets up a connection to an Erlang node.</p>
+ <p><c><![CDATA[erl_xconnect()]]></c> requires the IP address of the
+ remote host and the alivename of the remote node to be
+ specified. <c><![CDATA[erl_connect()]]></c> provides an alternative
interface, and determines the information from the node name
provided.</p>
- <p><c><![CDATA[addr]]></c> is the 32-bit IP address of the remote host.</p>
- <p><c><![CDATA[alive]]></c> is the alivename of the remote node.</p>
- <p><c><![CDATA[node]]></c> is the name of the remote node.</p>
- <p>These functions return an open file descriptor on success, or
- a negative value indicating that an error occurred --- in
- which case they will set <c><![CDATA[erl_errno]]></c> to one of:</p>
+ <list type="bulleted">
+ <item><c><![CDATA[addr]]></c> is the 32-bit IP address of the remote
+ host.</item>
+ <item><c><![CDATA[alive]]></c> is the alivename of the remote node.
+ </item>
+ <item><c><![CDATA[node]]></c> is the name of the remote node.</item>
+ </list>
+ <p>Returns an open file descriptor on success, otherwise a negative
+ value. In the latter case <c><![CDATA[erl_errno]]></c> is set to one
+ of:</p>
<taglist>
<tag><c><![CDATA[EHOSTUNREACH]]></c></tag>
- <item>The remote host <c><![CDATA[node]]></c> is unreachable</item>
+ <item>The remote host <c><![CDATA[node]]></c> is unreachable.</item>
<tag><c><![CDATA[ENOMEM]]></c></tag>
- <item>No more memory available.</item>
+ <item>No more memory is available.</item>
<tag><c><![CDATA[EIO]]></c></tag>
<item>I/O error.</item>
</taglist>
- <p>Additionally, <c><![CDATA[errno]]></c> values from
- <c><![CDATA[socket]]></c><em>(2)</em> and <c><![CDATA[connect]]></c><em>(2)</em>
- system calls may be propagated into <c><![CDATA[erl_errno]]></c>.</p>
+ <p>Also, <c><![CDATA[errno]]></c> values from
+ <c><![CDATA[socket]]></c><em>(2)</em> and
+ <c><![CDATA[connect]]></c><em>(2)</em>
+ system calls can be propagated into <c><![CDATA[erl_errno]]></c>.</p>
+ <p><em>Example:</em></p>
<code type="none"><![CDATA[
#define NODE "[email protected]"
#define ALIVE "madonna"
@@ -135,10 +148,12 @@ erl_xconnect( &addr , ALIVE );
]]></code>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_connect_init(number, cookie, creation)</nametext></name>
<name><ret>int</ret><nametext>erl_connect_xinit(host, alive, node, addr, cookie, creation)</nametext></name>
<fsummary>Initialize communication.</fsummary>
+ <marker id="erl_connect_init"/>
<type>
<v>int number;</v>
<v>char *cookie;</v>
@@ -147,47 +162,72 @@ erl_xconnect( &addr , ALIVE );
<v>struct in_addr *addr;</v>
</type>
<desc>
- <p>These functions initialize the <c><![CDATA[erl_connect]]></c>
- module. In particular, they are used to identify the name of the
+ <p>Initializes the <c><![CDATA[erl_connect]]></c> module.
+ In particular, these functions are used to identify the name of the
C-node from which they are called. One of these functions must
- be called before any of the other functions in the erl_connect
+ be called before any of the other functions in the <c>erl_connect</c>
module are used.</p>
- <p><c><![CDATA[erl_connect_xinit()]]></c> stores for later use information about
- the node's host name <c><![CDATA[host]]></c>, alive name <c><![CDATA[alive]]></c>, node
- name <c><![CDATA[node]]></c>, IP address <c><![CDATA[addr]]></c>, cookie <c><![CDATA[cookie]]></c>,
- and creation number <c><![CDATA[creation]]></c>. <c><![CDATA[erl_connect_init()]]></c>
- provides an alternative interface which does not require as much
- information from the caller. Instead, <c><![CDATA[erl_connect_init()]]></c>
- uses <c><![CDATA[gethostbyname()]]></c> to obtain default values.
- </p>
- <p>If you use <c><![CDATA[erl_connect_init()]]></c> your node will have a
- short name, i.e., it will not be fully qualified. If you need to
- use fully qualified (a.k.a. long) names, use
- <c><![CDATA[erl_connect_xinit()]]></c> instead.
- </p>
- <p><c><![CDATA[host]]></c> is the name of the host on which the node is running.</p>
- <p><c><![CDATA[alive]]></c> is the alivename of the node.</p>
- <p><c><![CDATA[node]]></c> is the name of the node. The nodename should
- be of the form <em>alivename@hostname</em>.</p>
- <p><c><![CDATA[addr]]></c> is the 32-bit IP address of <c><![CDATA[host]]></c>.</p>
- <p><c><![CDATA[cookie]]></c> is the authorization string required for access
- to the remote node. If NULL the user HOME directory is
- searched for a cookie file <c><![CDATA[.erlang.cookie]]></c>. The path to
- the home directory is retrieved from the environment variable
- <c><![CDATA[HOME]]></c> on Unix and from the <c><![CDATA[HOMEDRIVE]]></c> and
- <c><![CDATA[HOMEPATH]]></c> variables on Windows. Refer to the <c><![CDATA[auth]]></c>
- module for more details.</p>
- <p><c><![CDATA[creation]]></c> helps identify a particular instance of a C
- node. In particular, it can help prevent us from receiving
- messages sent to an earlier process with the same registered
- name.</p>
- <p>A C node acting as a server will be assigned a creation number
+ <p><c><![CDATA[erl_connect_xinit()]]></c> stores for later use
+ information about:</p>
+ <list type="bulleted">
+ <item>Hostname of the node, <c><![CDATA[host]]></c></item>
+ <item>Alivename, <c><![CDATA[alive]]></c></item>
+ <item>Node name, <c><![CDATA[node]]></c></item>
+ <item>IP address, <c><![CDATA[addr]]></c></item>
+ <item>Cookie, <c><![CDATA[cookie]]></c></item>
+ <item>Creation number, <c><![CDATA[creation]]></c></item>
+ </list>
+ <p><c><![CDATA[erl_connect_init()]]></c>
+ provides an alternative interface that does not require as much
+ information from the caller. Instead,
+ <c><![CDATA[erl_connect_init()]]></c>
+ uses <c><![CDATA[gethostbyname()]]></c> to obtain default values.</p>
+ <p>If you use <c><![CDATA[erl_connect_init()]]></c>, your node will
+ have a short name, that is, it will not be fully qualified. If you
+ need to use fully qualified (long) names, use
+ <c><![CDATA[erl_connect_xinit()]]></c> instead.</p>
+ <list type="bulleted">
+ <item>
+ <p><c><![CDATA[host]]></c> is the name of the host on which the node
+ is running.</p>
+ </item>
+ <item>
+ <p><c><![CDATA[alive]]></c> is the alivename of the node.</p>
+ </item>
+ <item>
+ <p><c><![CDATA[node]]></c> is the node name. It is to
+ be of the form <em>alivename@hostname</em>.</p>
+ </item>
+ <item>
+ <p><c><![CDATA[addr]]></c> is the 32-bit IP address of
+ <c><![CDATA[host]]></c>.</p>
+ </item>
+ <item>
+ <p><c><![CDATA[cookie]]></c> is the authorization string required
+ for access to the remote node. If <c>NULL</c>, the user
+ <c>HOME</c> directory is searched for a cookie file
+ <c><![CDATA[.erlang.cookie]]></c>. The path to
+ the home directory is retrieved from environment variable
+ <c><![CDATA[HOME]]></c> on Unix and from the
+ <c><![CDATA[HOMEDRIVE]]></c> and
+ <c><![CDATA[HOMEPATH]]></c> variables on Windows. For more
+ details, see the <seealso marker="kernel:auth">
+ <c>kernel:auth</c></seealso> module.</p>
+ </item>
+ <item>
+ <p><c><![CDATA[creation]]></c> helps identifying a particular
+ instance of a C-node. In particular, it can help prevent us from
+ receiving messages sent to an earlier process with the same
+ registered name.</p>
+ </item>
+ </list>
+ <p>A C-node acting as a server is assigned a creation number
when it calls <c><![CDATA[erl_publish()]]></c>.</p>
- <p><c><![CDATA[number]]></c> is used by <c><![CDATA[erl_connect_init()]]></c> to
- construct the actual node name. In the second example shown
- below, <em>"[email protected]"</em> will be the resulting node
- name.</p>
- <p>Example 1:</p>
+ <p><c><![CDATA[number]]></c> is used by
+ <c><![CDATA[erl_connect_init()]]></c> to
+ construct the actual node name. In Example 2
+ below, <em>"[email protected]"</em> is the resulting node name.</p>
+ <p><em>Example 1:</em></p>
<code type="none"><![CDATA[
struct in_addr addr;
addr = inet_addr("150.236.14.75");
@@ -199,13 +239,14 @@ if (!erl_connect_xinit("chivas",
0)
erl_err_quit("<ERROR> when initializing !");
]]></code>
- <p>Example 2:</p>
+ <p><em>Example 2:</em></p>
<code type="none"><![CDATA[
if (!erl_connect_init(17, "samplecookiestring...", 0))
erl_err_quit("<ERROR> when initializing !");
]]></code>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_publish(port)</nametext></name>
<fsummary>Publish a node name.</fsummary>
@@ -213,66 +254,74 @@ if (!erl_connect_init(17, "samplecookiestring...", 0))
<v>int port;</v>
</type>
<desc>
- <p>These functions are used by a server process to register
+ <p>This function is used by a server process to register
with the local name server <em>epmd</em>, thereby allowing
other processes to send messages by using the registered name.
- Before calling either of these functions, the process should
- have called <c><![CDATA[bind()]]></c> and <c><![CDATA[listen()]]></c> on an open socket.</p>
- <p><c><![CDATA[port]]></c> is the local name to register, and should be the
- same as the port number that was previously bound to the socket.</p>
- <p>To unregister with epmd, simply close the returned
- descriptor.
- </p>
- <p>On success, the functions return a descriptor connecting the
- calling process to epmd. On failure, they return -1 and set
- <c><![CDATA[erl_errno]]></c> to:</p>
+ Before calling this function, the process should
+ have called <c><![CDATA[bind()]]></c> and <c><![CDATA[listen()]]></c>
+ on an open socket.</p>
+ <p><c><![CDATA[port]]></c> is the local name to register, and is to be
+ the same as the port number that was previously bound to the
+ socket.</p>
+ <p>To unregister with EPMD, simply close the returned descriptor.</p>
+ <p>On success, a descriptor connecting the calling process to EPMD is
+ returned. On failure, <c>-1</c> is returned and
+ <c><![CDATA[erl_errno]]></c> is set to:</p>
<taglist>
<tag><c><![CDATA[EIO]]></c></tag>
- <item>I/O error</item>
+ <item>I/O error.</item>
</taglist>
- <p>Additionally, <c><![CDATA[errno]]></c> values from <c><![CDATA[socket]]></c><em>(2)</em>
- and <c><![CDATA[connect]]></c><em>(2)</em> system calls may be propagated
- into <c><![CDATA[erl_errno]]></c>.
- </p>
+ <p>Also, <c><![CDATA[errno]]></c> values from
+ <c><![CDATA[socket]]></c><em>(2)</em>
+ and <c><![CDATA[connect]]></c><em>(2)</em> system calls can be
+ propagated into <c><![CDATA[erl_errno]]></c>.</p>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_receive(fd, bufp, bufsize)</nametext></name>
<fsummary>Receive a message.</fsummary>
+ <marker id="erl_receive"/>
<type>
<v>int fd;</v>
<v>char *bufp;</v>
<v>int bufsize;</v>
</type>
<desc>
- <p>This function receives a message consisting of a sequence
+ <p>Receives a message consisting of a sequence
of bytes in the Erlang external format.</p>
- <p><c><![CDATA[fd]]></c> is an open descriptor to an Erlang connection.</p>
- <p><c><![CDATA[bufp]]></c> is a buffer large enough to hold the expected
- message. </p>
- <p><c><![CDATA[bufsize]]></c> indicates the size of <c><![CDATA[bufp]]></c>.</p>
- <p>If a <em>tick</em> occurs, i.e., the Erlang node on the
+ <list type="bulleted">
+ <item><c><![CDATA[fd]]></c> is an open descriptor to an Erlang
+ connection.</item>
+ <item><c><![CDATA[bufp]]></c> is a buffer large enough to hold the
+ expected message.</item>
+ <item><c><![CDATA[bufsize]]></c> indicates the size of
+ <c><![CDATA[bufp]]></c>.</item>
+ </list>
+ <p>If a <em>tick</em> occurs, that is, the Erlang node on the
other end of the connection has polled this node to see if it
- is still alive, the function will return <c><![CDATA[ERL_TICK]]></c> and
- no message will be placed in the buffer. Also,
- <c><![CDATA[erl_errno]]></c> will be set to <c><![CDATA[EAGAIN]]></c>.</p>
+ is still alive, the function returns <c><![CDATA[ERL_TICK]]></c> and
+ no message is placed in the buffer. Also,
+ <c><![CDATA[erl_errno]]></c> is set to <c><![CDATA[EAGAIN]]></c>.</p>
<p>On success, the message is placed in the specified buffer
and the function returns the number of bytes actually read. On
- failure, the function returns a negative value and will set
+ failure, the function returns a negative value and sets
<c><![CDATA[erl_errno]]></c> to one of:</p>
<taglist>
<tag><c><![CDATA[EAGAIN]]></c></tag>
<item>Temporary error: Try again.</item>
<tag><c><![CDATA[EMSGSIZE]]></c></tag>
- <item>Buffer too small.</item>
+ <item>Buffer is too small.</item>
<tag><c><![CDATA[EIO]]></c></tag>
<item>I/O error.</item>
</taglist>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_receive_msg(fd, bufp, bufsize, emsg)</nametext></name>
- <fsummary>Receive and decodes a message.</fsummary>
+ <fsummary>Receive and decode a message.</fsummary>
+ <marker id="erl_receive_msg"/>
<type>
<v>int fd;</v>
<v>unsigned char *bufp;</v>
@@ -280,14 +329,20 @@ if (!erl_connect_init(17, "samplecookiestring...", 0))
<v>ErlMessage *emsg;</v>
</type>
<desc>
- <p>This function receives the message into the specified buffer,
- and decodes into the <c><![CDATA[(ErlMessage *) emsg]]></c>.</p>
- <p><c><![CDATA[fd]]></c> is an open descriptor to an Erlang connection.</p>
- <p><c><![CDATA[bufp]]></c> is a buffer large enough to hold the expected message.</p>
- <p><c><![CDATA[bufsize]]></c> indicates the size of <c><![CDATA[bufp]]></c>.</p>
- <p><c><![CDATA[emsg]]></c> is a pointer to an <c><![CDATA[ErlMessage]]></c> structure,
- into which the message will be decoded. <c><![CDATA[ErlMessage]]></c> is
- defined as follows:</p>
+ <p>Receives the message into the specified buffer
+ and decodes into <c><![CDATA[(ErlMessage *) emsg]]></c>.</p>
+ <list type="bulleted">
+ <item><c><![CDATA[fd]]></c> is an open descriptor to an Erlang
+ connection.</item>
+ <item><c><![CDATA[bufp]]></c> is a buffer large enough to hold the
+ expected message.</item>
+ <item><c><![CDATA[bufsize]]></c> indicates the size of
+ <c><![CDATA[bufp]]></c>.</item>
+ <item>><c><![CDATA[emsg]]></c> is a pointer to an
+ <c><![CDATA[ErlMessage]]></c> structure
+ into which the message will be decoded.
+ <c><![CDATA[ErlMessage]]></c> is defined as follows:</item>
+ </list>
<code type="none"><![CDATA[
typedef struct {
int type;
@@ -299,81 +354,95 @@ typedef struct {
]]></code>
<note>
<p>The definition of <c><![CDATA[ErlMessage]]></c> has changed since
- earlier versions of Erl_Interface.</p>
+ earlier versions of <c>Erl_Interface</c>.</p>
</note>
- <p><c><![CDATA[type]]></c> identifies the type of message, one of
- <c><![CDATA[ERL_SEND]]></c>, <c><![CDATA[ERL_REG_SEND]]></c>, <c><![CDATA[ERL_LINK]]></c>,
- <c><![CDATA[ERL_UNLINK]]></c> and <c><![CDATA[ERL_EXIT]]></c>.
- </p>
- <p>If <c><![CDATA[type]]></c> contains <c><![CDATA[ERL_SEND]]></c>
- this indicates that an ordinary send operation has taken
- place, and <c><![CDATA[emsg->to]]></c> contains the Pid of the
- recipient. If <c><![CDATA[type]]></c> contains <c><![CDATA[ERL_REG_SEND]]></c> then a
- registered send operation took place, and <c><![CDATA[emsg->from]]></c>
- contains the Pid of the sender. In both cases, the actual
- message will be in <c><![CDATA[emsg->msg]]></c>.
- </p>
- <p>If <c><![CDATA[type]]></c> contains one of <c><![CDATA[ERL_LINK]]></c> or
- <c><![CDATA[ERL_UNLINK]]></c>, then <c><![CDATA[emsg->to]]></c> and <c><![CDATA[emsg->from]]></c>
- contain the pids of the sender and recipient of the link or unlink.
- <c><![CDATA[emsg->msg]]></c> is not used in these cases.
- </p>
- <p>If <c><![CDATA[type]]></c> contains <c><![CDATA[ERL_EXIT]]></c>, then this
- indicates that a link has been broken. In this case,
- <c><![CDATA[emsg->to]]></c> and <c><![CDATA[emsg->from]]></c> contain the pids of the
- linked processes, and <c><![CDATA[emsg->msg]]></c> contains the reason for
- the exit.
- </p>
+ <p><c><![CDATA[type]]></c> identifies the type of message, one of the
+ following:</p>
+ <taglist>
+ <tag><c><![CDATA[ERL_SEND]]></c></tag>
+ <item>
+ <p>An ordinary send operation has occurred and
+ <c><![CDATA[emsg->to]]></c> contains the pid of the recipient.
+ The message is in <c><![CDATA[emsg->msg]]></c>.</p>
+ </item>
+ <tag><c><![CDATA[ERL_REG_SEND]]></c></tag>
+ <item>
+ <p>A registered send operation has occurred and
+ <c><![CDATA[emsg->from]]></c> contains the pid of the sender.
+ The message is in <c><![CDATA[emsg->msg]]></c>.</p>
+ </item>
+ <tag><c><![CDATA[ERL_LINK]]></c> or <c><![CDATA[ERL_UNLINK]]></c>
+ </tag>
+ <item>
+ <p><c><![CDATA[emsg->to]]></c> and <c><![CDATA[emsg->from]]></c>
+ contain the pids of the sender and recipient of the link or
+ unlink. <c><![CDATA[emsg->msg]]></c> is not used.</p>
+ </item>
+ <tag><c><![CDATA[ERL_EXIT]]></c></tag>
+ <item>
+ <p>A link is broken. <c><![CDATA[emsg->to]]></c> and
+ <c><![CDATA[emsg->from]]></c> contain the pids of the linked
+ processes, and <c><![CDATA[emsg->msg]]></c> contains the reason
+ for the exit.</p>
+ </item>
+ </taglist>
<note>
<p>It is the caller's responsibility to release the
- memory pointed to by <c><![CDATA[emsg->msg]]></c>, <c><![CDATA[emsg->to]]></c> and
+ memory pointed to by <c><![CDATA[emsg->msg]]></c>,
+ <c><![CDATA[emsg->to]]></c>, and
<c><![CDATA[emsg->from]]></c>.</p>
</note>
- <p>If a <em>tick</em> occurs, i.e., the Erlang node on the
+ <p>If a <em>tick</em> occurs, that is, the Erlang node on the
other end of the connection has polled this node to see if it
- is still alive, the function will return <c><![CDATA[ERL_TICK]]></c>
+ is still alive, the function returns <c><![CDATA[ERL_TICK]]></c>
indicating that the tick has been received and responded to,
- but no message will be placed in the buffer. In this case you
- should call <c><![CDATA[erl_receive_msg()]]></c> again.</p>
+ but no message is placed in the buffer. In this case you
+ are to call <c><![CDATA[erl_receive_msg()]]></c> again.</p>
<p>On success, the function returns <c><![CDATA[ERL_MSG]]></c> and the
- <c><![CDATA[Emsg]]></c> struct will be initialized as described above, or
+ <c><![CDATA[Emsg]]></c> struct is initialized as described above, or
<c><![CDATA[ERL_TICK]]></c>, in which case no message is returned. On
- failure, the function returns <c><![CDATA[ERL_ERROR]]></c> and will set
+ failure, the function returns <c><![CDATA[ERL_ERROR]]></c> and sets
<c><![CDATA[erl_errno]]></c> to one of:</p>
<taglist>
<tag><c><![CDATA[EMSGSIZE]]></c></tag>
- <item>Buffer too small.</item>
+ <item>Buffer is too small.</item>
<tag><c><![CDATA[ENOMEM]]></c></tag>
- <item>No more memory available.</item>
+ <item>No more memory is available.</item>
<tag><c><![CDATA[EIO]]></c></tag>
<item>I/O error.</item>
</taglist>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_reg_send(fd, to, msg)</nametext></name>
<fsummary>Send a message to a registered name.</fsummary>
+ <marker id="erl_reg_send"/>
<type>
<v>int fd;</v>
<v>char *to;</v>
<v>ETERM *msg;</v>
</type>
<desc>
- <p>This function sends an Erlang term to a registered process.</p>
- <p><c><![CDATA[fd]]></c> is an open descriptor to an Erlang connection.</p>
- <p><c><![CDATA[to]]></c> is a string containing the registered name of
- the intended recipient of the message.</p>
- <p><c><![CDATA[msg]]></c> is the Erlang term to be sent.</p>
- <p>The function returns 1 if successful, otherwise 0 --- in
- which case it will set <c><![CDATA[erl_errno]]></c> to one of:</p>
+ <p>Sends an Erlang term to a registered process.</p>
+ <list type="bulleted">
+ <item><c><![CDATA[fd]]></c> is an open descriptor to an Erlang
+ connection.</item>
+ <item><c><![CDATA[to]]></c> is a string containing the registered name
+ of the intended recipient of the message.</item>
+ <item><c><![CDATA[msg]]></c> is the Erlang term to be sent.</item>
+ </list>
+ <p>Returns <c>1</c> on success, otherwise <c>0</c>. In
+ the latter case <c><![CDATA[erl_errno]]></c> is set to one of:</p>
<taglist>
<tag><c><![CDATA[ENOMEM]]></c></tag>
- <item>No more memory available.</item>
+ <item>No more memory is available.</item>
<tag><c><![CDATA[EIO]]></c></tag>
<item>I/O error.</item>
</taglist>
</desc>
</func>
+
<func>
<name><ret>ETERM *</ret><nametext>erl_rpc(fd, mod, fun, args)</nametext></name>
<name><ret>int</ret><nametext>erl_rpc_from(fd, timeout, emsg)</nametext></name>
@@ -386,81 +455,97 @@ typedef struct {
<v>ErlMessage *emsg;</v>
</type>
<desc>
- <p>These functions support calling Erlang functions on remote nodes.
- <c><![CDATA[erl_rpc_to()]]></c> sends an rpc request to a remote node and
- <c><![CDATA[erl_rpc_from()]]></c> receives the results of such a call.
- <c><![CDATA[erl_rpc()]]></c> combines the functionality of these two functions
- by sending an rpc request and waiting for the results. See also
- <c><![CDATA[rpc:call/4]]></c>. </p>
- <p><c><![CDATA[fd]]></c> is an open descriptor to an Erlang connection.</p>
- <p><c><![CDATA[timeout]]></c> is the maximum time (in ms) to wait for
- results. Specify <c><![CDATA[ERL_NO_TIMEOUT]]></c> to wait forever.
- When erl_rpc() calls erl_rpc_from(), the call will never
- timeout.</p>
- <p><c><![CDATA[mod]]></c> is the name of the module containing the function
- to be run on the remote node.</p>
- <p><c><![CDATA[fun]]></c> is the name of the function to run.</p>
- <p><c><![CDATA[args]]></c> is an Erlang list, containing the arguments to be
- passed to the function. </p>
- <p><c><![CDATA[emsg]]></c> is a message containing the result of the
- function call.</p>
- <p>The actual message returned by the rpc server
- is a 2-tuple <c><![CDATA[{rex,Reply}]]></c>. If you are using
- <c><![CDATA[erl_rpc_from()]]></c> in your code then this is the message you
- will need to parse. If you are using <c><![CDATA[erl_rpc()]]></c> then the
+ <p>Supports calling Erlang functions on remote nodes.
+ <c><![CDATA[erl_rpc_to()]]></c> sends an RPC request to a remote node
+ and <c><![CDATA[erl_rpc_from()]]></c> receives the results of such a
+ call. <c><![CDATA[erl_rpc()]]></c> combines the functionality of
+ these two functions by sending an RPC request and waiting for the
+ results. See also <seealso marker="kernel:rpc#call/4">
+ <c>rpc:call/4</c></seealso> in <c>Kernel</c>.</p>
+ <list type="bulleted">
+ <item><c><![CDATA[fd]]></c> is an open descriptor to an Erlang
+ connection.</item>
+ <item><c><![CDATA[timeout]]></c> is the maximum time (in milliseconds)
+ to wait for
+ results. To wait forever, specify <c><![CDATA[ERL_NO_TIMEOUT]]></c>.
+ When <c>erl_rpc()</c> calls <c>erl_rpc_from()</c>, the call will
+ never timeout.</item>
+ <item><c><![CDATA[mod]]></c> is the name of the module containing the
+ function to be run on the remote node.</item>
+ <item><c><![CDATA[fun]]></c> is the name of the function to run.
+ </item>
+ <item><c><![CDATA[args]]></c> is an Erlang list, containing the
+ arguments to be passed to the function.</item>
+ <item><c><![CDATA[emsg]]></c> is a message containing the result of
+ the function call.</item>
+ </list>
+ <p>The actual message returned by the RPC server
+ is a 2-tuple <c><![CDATA[{rex,Reply}]]></c>. If you use
+ <c><![CDATA[erl_rpc_from()]]></c> in your code, this is the message
+ you will need to parse. If you use <c><![CDATA[erl_rpc()]]></c>, the
tuple itself is parsed for you, and the message returned to your
- program is the erlang term containing <c><![CDATA[Reply]]></c> only. Replies
- to rpc requests are always ERL_SEND messages.
- </p>
+ program is the Erlang term containing <c><![CDATA[Reply]]></c> only.
+ Replies to RPC requests are always <c>ERL_SEND</c> messages.</p>
<note>
<p>It is the caller's responsibility to free the returned
- <c><![CDATA[ETERM]]></c> structure as well as the memory pointed to by
- <c><![CDATA[emsg->msg]]></c> and <c><![CDATA[emsg->to]]></c>. </p>
+ <c><![CDATA[ETERM]]></c> structure and the memory pointed to by
+ <c><![CDATA[emsg->msg]]></c> and <c><![CDATA[emsg->to]]></c>.</p>
</note>
- <p><c><![CDATA[erl_rpc()]]></c> returns the remote function's return value (or
- <c><![CDATA[NULL]]></c> if it failed). <c><![CDATA[erl_rpc_to()]]></c> returns 0 on
- success, and a negative number on failure. <c><![CDATA[erl_rcp_from()]]></c>
- returns <c><![CDATA[ERL_MSG]]></c> when successful (with <c><![CDATA[Emsg]]></c> now
- containing the reply tuple), and one of <c><![CDATA[ERL_TICK]]></c>,
- <c><![CDATA[ERL_TIMEOUT]]></c> and <c><![CDATA[ERL_ERROR]]></c> otherwise. When failing,
+ <p><c><![CDATA[erl_rpc()]]></c> returns the remote function's return
+ value on success, otherwise <c><![CDATA[NULL]]></c>.</p>
+ <p><c><![CDATA[erl_rpc_to()]]></c> returns <c>0</c> on
+ success, otherwise a negative number.</p>
+ <p><c><![CDATA[erl_rcp_from()]]></c> returns <c><![CDATA[ERL_MSG]]></c>
+ on success (with <c><![CDATA[Emsg]]></c> now
+ containing the reply tuple), otherwise one of
+ <c><![CDATA[ERL_TICK]]></c>, <c><![CDATA[ERL_TIMEOUT]]></c>, or
+ <c><![CDATA[ERL_ERROR]]></c>.</p>
+ <p>When failing,
all three functions set <c><![CDATA[erl_errno]]></c> to one of:</p>
<taglist>
<tag><c><![CDATA[ENOMEM]]></c></tag>
- <item>No more memory available.</item>
+ <item>No more memory is available.</item>
<tag><c><![CDATA[EIO]]></c></tag>
<item>I/O error.</item>
<tag><c><![CDATA[ETIMEDOUT]]></c></tag>
- <item>Timeout expired.</item>
+ <item>Timeout has expired.</item>
<tag><c><![CDATA[EAGAIN]]></c></tag>
<item>Temporary error: Try again.</item>
</taglist>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_send(fd, to, msg)</nametext></name>
<fsummary>Send a message.</fsummary>
+ <marker id="erl_send"/>
<type>
<v>int fd;</v>
<v>ETERM *to, *msg;</v>
</type>
<desc>
- <p>This function sends an Erlang term to a process.</p>
- <p><c><![CDATA[fd]]></c> is an open descriptor to an Erlang connection.</p>
- <p><c><![CDATA[to]]></c> is an Erlang term containing the Pid of the
- intended recipient of the message.</p>
- <p><c><![CDATA[msg]]></c> is the Erlang term to be sent.</p>
- <p>The function returns 1 if successful, otherwise 0 --- in
- which case it will set <c><![CDATA[erl_errno]]></c> to one of:</p>
+ <p>Sends an Erlang term to a process.</p>
+ <list type="bulleted">
+ <item><c><![CDATA[fd]]></c> is an open descriptor to an Erlang
+ connection.</item>
+ <item><c><![CDATA[to]]></c> is an Erlang term containing the pid of
+ the intended recipient of the message.</item>
+ <item>><c><![CDATA[msg]]></c> is the Erlang term to be sent.</item>
+ </list>
+ <p>Returns <c>1</c> on success, otherwise <c>0</c>. In
+ the latter case <c><![CDATA[erl_errno]]></c> is set to one of:</p>
<taglist>
<tag><c><![CDATA[EINVAL]]></c></tag>
- <item>Invalid argument: <c><![CDATA[to]]></c> is not a valid Erlang pid.</item>
+ <item>Invalid argument: <c><![CDATA[to]]></c> is not a valid Erlang
+ pid.</item>
<tag><c><![CDATA[ENOMEM]]></c></tag>
- <item>No more memory available.</item>
+ <item>No more memory is available.</item>
<tag><c><![CDATA[EIO]]></c></tag>
<item>I/O error.</item>
</taglist>
</desc>
</func>
+
<func>
<name><ret>const char *</ret><nametext>erl_thisalivename()</nametext></name>
<name><ret>const char *</ret><nametext>erl_thiscookie()</nametext></name>
@@ -469,11 +554,13 @@ typedef struct {
<name><ret>const char *</ret><nametext>erl_thisnodename()</nametext></name>
<fsummary>Retrieve some values.</fsummary>
<desc>
- <p>These functions can be used to retrieve information about
- the C Node. These values are initially set with
- <c><![CDATA[erl_connect_init()]]></c> or <c><![CDATA[erl_connect_xinit()]]></c>.</p>
+ <p>Retrieves information about
+ the C-node. These values are initially set with
+ <c><![CDATA[erl_connect_init()]]></c> or
+ <c><![CDATA[erl_connect_xinit()]]></c>.</p>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_unpublish(alive)</nametext></name>
<fsummary>Forcefully unpublish a node name.</fsummary>
@@ -482,28 +569,28 @@ typedef struct {
</type>
<desc>
<p>This function can be called by a process to unregister a
- specified node from epmd on the localhost. This is however usually not
- allowed, unless epmd was started with the -relaxed_command_check
- flag, which it normally isn't.</p>
-
- <p>To unregister a node you have published, you should instead
- close the descriptor that was returned by
- <c><![CDATA[ei_publish()]]></c>.</p>
-
+ specified node from EPMD on the local host. This is, however, usually
+ not allowed, unless EPMD was started with flag
+ <c>-relaxed_command_check</c>, which it normally is not.</p>
+ <p>To unregister a node you have published, you should instead
+ close the descriptor that was returned by
+ <c><![CDATA[ei_publish()]]></c>.</p>
<warning>
<p>This function is deprecated and will be removed in a future
- release.</p>
+ release.</p>
</warning>
- <p><c><![CDATA[alive]]></c> is the name of the node to unregister, i.e., the
- first component of the nodename, without the <c><![CDATA[@hostname]]></c>.</p>
- <p>If the node was successfully unregistered from epmd, the
- function returns 0. Otherwise, it returns -1 and sets
- <c><![CDATA[erl_errno]]></c> is to <c><![CDATA[EIO]]></c>.</p>
+ <p><c><![CDATA[alive]]></c> is the name of the node to unregister, that
+ is, the first component of the node name, without
+ <c><![CDATA[@hostname]]></c>.</p>
+ <p>If the node was successfully unregistered from EPMD, <c>0</c> is
+ returned, otherwise <c>-1</c> is returned and
+ <c><![CDATA[erl_errno]]></c> is set to <c><![CDATA[EIO]]></c>.</p>
</desc>
</func>
+
<func>
<name><ret>int</ret><nametext>erl_xreceive_msg(fd, bufpp, bufsizep, emsg)</nametext></name>
- <fsummary>Receive and decodes a message.</fsummary>
+ <fsummary>Receive and decode a message.</fsummary>
<type>
<v>int fd;</v>
<v>unsigned char **bufpp;</v>
@@ -511,33 +598,35 @@ typedef struct {
<v>ErlMessage *emsg;</v>
</type>
<desc>
- <p>This function is similar to <c><![CDATA[erl_receive_msg]]></c>. The
- difference is that <c><![CDATA[erl_xreceive_msg]]></c> expects the buffer to
- have been allocated by <c><![CDATA[malloc]]></c>, and reallocates it if the received
- message does not fit into the original buffer. For that reason,
- both buffer and buffer length are given as pointers - their values
- may change by the call.
- </p>
+ <p>Similar to <c><![CDATA[erl_receive_msg]]></c>. The difference is
+ that <c><![CDATA[erl_xreceive_msg]]></c> expects the buffer to
+ have been allocated by <c><![CDATA[malloc]]></c>, and reallocates it
+ if the received
+ message does not fit into the original buffer. Therefore
+ both buffer and buffer length are given as pointers; their values
+ can change by the call.</p>
<p>On success, the function returns <c><![CDATA[ERL_MSG]]></c> and the
- <c><![CDATA[Emsg]]></c> struct will be initialized as described above, or
+ <c><![CDATA[Emsg]]></c> struct is initialized as described above, or
<c><![CDATA[ERL_TICK]]></c>, in which case no message is returned. On
- failure, the function returns <c><![CDATA[ERL_ERROR]]></c> and will set
+ failure, the function returns <c><![CDATA[ERL_ERROR]]></c> and sets
<c><![CDATA[erl_errno]]></c> to one of:</p>
<taglist>
<tag><c><![CDATA[EMSGSIZE]]></c></tag>
- <item>Buffer too small.</item>
+ <item>Buffer is too small.</item>
<tag><c><![CDATA[ENOMEM]]></c></tag>
- <item>No more memory available.</item>
+ <item>No more memory is available.</item>
<tag><c><![CDATA[EIO]]></c></tag>
<item>I/O error.</item>
</taglist>
</desc>
</func>
+
<func>
<name><ret>struct hostent</ret><nametext>*erl_gethostbyaddr(addr, length, type)</nametext></name>
<name><ret>struct hostent</ret><nametext>*erl_gethostbyaddr_r(addr, length, type, hostp, buffer, buflen, h_errnop)</nametext></name>
<name><ret>struct hostent</ret><nametext>*erl_gethostbyname(name)</nametext></name>
<name><ret>struct hostent</ret><nametext>*erl_gethostbyname_r(name, hostp, buffer, buflen, h_errnop)</nametext></name>
+
<fsummary>Name lookup functions.</fsummary>
<type>
<v>const char *name;</v>
@@ -550,7 +639,7 @@ typedef struct {
<v>int *h_errnop;</v>
</type>
<desc>
- <p>These are convenience functions for some common name lookup functions.</p>
+ <p>Convenience functions for some common name lookup functions.</p>
</desc>
</func>
</funcs>
@@ -558,12 +647,13 @@ typedef struct {
<section>
<title>Debug Information</title>
<p>If a connection attempt fails, the following can be checked:</p>
+
<list type="bulleted">
<item><c><![CDATA[erl_errno]]></c></item>
- <item>that the right cookie was used</item>
- <item>that <em>epmd</em> is running</item>
- <item>the remote Erlang node on the other side is running the same
- version of Erlang as the <c><![CDATA[erl_interface]]></c> library.</item>
+ <item>That the correct cookie was used</item>
+ <item>That EPMD is running</item>
+ <item>That the remote Erlang node on the other side is running the same
+ version of Erlang as the <c><![CDATA[erl_interface]]></c> library</item>
</list>
</section>
</cref>