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authorMagnus Lidén <[email protected]>2014-11-06 10:46:20 +0100
committerMagnus Lidén <[email protected]>2014-11-07 09:43:35 +0100
commit77f71fc05cc4eb378de0a16df6390b3781d18d36 (patch)
treef779cc5b5e0c8dd0933a25a4b99aa6852adf2107 /lib/kernel/doc
parent509163307c31bf4f98a638b47ee03a5b99eb2c73 (diff)
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Update documentation for buffer options
Diffstat (limited to 'lib/kernel/doc')
-rw-r--r--lib/kernel/doc/src/inet.xml61
1 files changed, 37 insertions, 24 deletions
diff --git a/lib/kernel/doc/src/inet.xml b/lib/kernel/doc/src/inet.xml
index 50e1cc290c..8dd311e5cd 100644
--- a/lib/kernel/doc/src/inet.xml
+++ b/lib/kernel/doc/src/inet.xml
@@ -138,7 +138,7 @@ fe80::204:acff:fe17:bf38
<name name="get_rc" arity="0"/>
<fsummary>Return a list of IP configuration parameters</fsummary>
<desc>
- <p>Returns the state of the Inet configuration database in
+ <p>Returns the state of the Inet configuration database in
form of a list of recorded configuration parameters. (See the
ERTS User's Guide, Inet configuration, for more information).
Only parameters with other than default values are returned.</p>
@@ -258,8 +258,8 @@ fe80::204:acff:fe17:bf38
<type name="socket_getopt"/>
<type name="socket_setopt"/>
<desc>
- <p>Gets one or more options for a socket.
- See <seealso marker="#setopts/2">setopts/2</seealso>
+ <p>Gets one or more options for a socket.
+ See <seealso marker="#setopts/2">setopts/2</seealso>
for a list of available options.</p>
<p>The number of elements in the returned <c><anno>OptionValues</anno></c>
list does not necessarily correspond to the number of options
@@ -278,14 +278,14 @@ fe80::204:acff:fe17:bf38
by the protocol level, the option number and either a binary
or the size, in bytes, of the
buffer in which the option value is to be stored. A binary
- should be used when the underlying <c>getsockopt</c> requires
+ should be used when the underlying <c>getsockopt</c> requires
<em>input</em>
in the argument field, in which case the size of the binary
should correspond to the required buffer
size of the return value. The supplied values in a <c>RawOptReq</c>
correspond to the second, third and fourth/fifth parameters to the
<c>getsockopt</c> call in the C socket API. The value stored
- in the buffer is returned as a binary <c>ValueBin</c>
+ in the buffer is returned as a binary <c>ValueBin</c>
where all values are coded in the native endianess.</p>
<p>Asking for and inspecting raw socket options require low
level information about the current operating system and TCP
@@ -306,7 +306,7 @@ fe80::204:acff:fe17:bf38
value to be a 32 bit integer. We could use the following
code to retrieve the value:</p>
<code type="none"><![CDATA[
- get_tcpi_sacked(Sock) ->
+ get_tcpi_sacked(Sock) ->
{ok,[{raw,_,_,Info}]} = inet:getopts(Sock,[{raw,6,11,92}]),
<<_:28/binary,TcpiSacked:32/native,_/binary>> = Info,
TcpiSacked.]]></code>
@@ -408,7 +408,7 @@ fe80::204:acff:fe17:bf38
<name name="parse_ipv6strict_address" arity="1" />
<fsummary>Parse an IPv6 address strict.</fsummary>
<desc>
- <p>Parses an IPv6 address string and returns an <a href="#type-ip6_address">ip6_address()</a>.
+ <p>Parses an IPv6 address string and returns an <a href="#type-ip6_address">ip6_address()</a>.
Does <b>not</b> accept IPv4 adresses.</p>
</desc>
</func>
@@ -613,15 +613,20 @@ fe80::204:acff:fe17:bf38
<marker id="option-buffer"></marker>
</item>
- <tag><c>{buffer, Size}</c></tag>
+ <tag><c>{buffer, Size}</c></tag>
<item>
- <p>Determines the size of the user-level software buffer used by
- the driver. Not to be confused with <c>sndbuf</c>
- and <c>recbuf</c> options which correspond to
- the kernel socket buffers. It is recommended
- to have <c>val(buffer) &gt;= max(val(sndbuf),val(recbuf))</c>.
- In fact, the <c>val(buffer)</c> is automatically set to
- the above maximum when <c>sndbuf</c> or <c>recbuf</c> values are set.</p>
+ <p>The size of the user-level software buffer used by
+ the driver. Not to be confused with <c>sndbuf</c>
+ and <c>recbuf</c> options which correspond to
+ the kernel socket buffers. It is recommended
+ to have <c>val(buffer) &gt;= max(val(sndbuf),val(recbuf))</c> to
+ avoid performance issues due to unnecessary copying.
+ In fact, the <c>val(buffer)</c> is automatically set to
+ the above maximum when <c>sndbuf</c> or <c>recbuf</c> values are set.
+ However, since the actual sizes set for <c>sndbuf</c> and <c>recbuf</c>
+ usually becomes larger, you are encouraged to use
+ <seealso marker="inet#getopts/2"><c>inet:getopts/2</c></seealso>
+ to analyze the behavior of your operating system.</p>
</item>
<tag><c>{delay_send, Boolean}</c></tag>
@@ -998,8 +1003,12 @@ setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp
</item>
<tag><c>{recbuf, Size}</c></tag>
<item>
- <p>Gives the size of the receive buffer to use for
- the socket.</p>
+ <p>The minimum size of the receive buffer to use for
+ the socket. You are encouraged to use
+ <seealso marker="inet#getopts/2"><c>inet:getopts/2</c></seealso>,
+ to retrieve the actual size set by your operating system.
+
+ </p>
</item>
<tag><c>{reuseaddr, Boolean}</c></tag>
<item>
@@ -1030,20 +1039,24 @@ setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp
<tag><c>{sndbuf, Size}</c></tag>
<item>
- <p>Gives the size of the send buffer to use for the socket.</p>
+ <p>The minimum size of the send buffer to use for the socket.
+ You are encouraged to use
+ <seealso marker="inet#getopts/2"><c>inet:getopts/2</c></seealso>,
+ to retrieve the actual size set by your operating system.
+ </p>
</item>
<tag><c>{priority, Integer}</c></tag>
<item>
- <p>Sets the SO_PRIORITY socket level option on platforms where
- this is implemented. The behaviour and allowed range varies on
- different systems. The option is ignored on platforms where the
+ <p>Sets the SO_PRIORITY socket level option on platforms where
+ this is implemented. The behaviour and allowed range varies on
+ different systems. The option is ignored on platforms where the
option is not implemented. Use with caution.</p>
</item>
<tag><c>{tos, Integer}</c></tag>
<item>
- <p>Sets IP_TOS IP level options on platforms where this is
- implemented. The behaviour and allowed range varies on different
- systems. The option is ignored on platforms where the option is
+ <p>Sets IP_TOS IP level options on platforms where this is
+ implemented. The behaviour and allowed range varies on different
+ systems. The option is ignored on platforms where the option is
not implemented. Use with caution.</p>
</item>
</taglist>