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authorRickard Green <[email protected]>2012-09-16 02:45:32 +0200
committerRickard Green <[email protected]>2012-12-03 21:18:10 +0100
commit23c6f9e07a3cae7c05e55abd01ff798384241538 (patch)
treedc62a1976380ea69f3843e1d53ef53526fdabd3e /erts/doc
parent34fc6f243f8a462f4b2370a9fe5376df1ca08f1d (diff)
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Add erl_drv_[send|output]_term
Diffstat (limited to 'erts/doc')
-rw-r--r--erts/doc/src/erl_driver.xml104
1 files changed, 84 insertions, 20 deletions
diff --git a/erts/doc/src/erl_driver.xml b/erts/doc/src/erl_driver.xml
index 4fd74b783e..fcce962557 100644
--- a/erts/doc/src/erl_driver.xml
+++ b/erts/doc/src/erl_driver.xml
@@ -123,12 +123,20 @@
different threads. This, however, is not a problem for any
function in this API, since the emulator has control over
these threads.</p>
- <note>
- <p>Functions not explicitly documented as thread-safe are
- <em>not</em> thread-safe. Also note that some functions
+ <warning>
+ <p>Functions not explicitly documented as thread safe are
+ <em>not</em> thread safe. Also note that some functions
are <em>only</em> thread safe when used in a runtime
system with SMP support.</p>
- </note>
+ <p>A function not explicitly documented as thread safe may at
+ some point in time have a thread safe implementation in the
+ runtime system. Such an implementation may however change to
+ a thread <em>unsafe</em> implementation at any time <em>without
+ any notice</em> at all.
+ </p>
+ <p><em>Only use functions explicitly documented as thread safe
+ from arbitrary threads.</em></p>
+ </warning>
</description>
<section>
@@ -1570,6 +1578,8 @@ typedef struct ErlIOVec {
<desc>
<marker id="driver_connected"></marker>
<p>This function returns the port owner process.</p>
+ <p>Note that this function is <em>not</em> thread-safe, not
+ even when the emulator with SMP support is used.</p>
</desc>
</func>
<func>
@@ -1597,22 +1607,32 @@ typedef struct ErlIOVec {
<tag><seealso marker="driver_entry#call">call</seealso></tag>
<item>Called from <c>erlang:port_call/3</c></item>
</taglist>
+ <p>Note that this function is <em>not</em> thread-safe, not
+ even when the emulator with SMP support is used.</p>
</desc>
</func>
<func>
- <name><ret>int</ret><nametext>driver_output_term(ErlDrvPort port, ErlDrvTermData* term, int n)</nametext></name>
+ <name><ret>int</ret><nametext>erl_drv_output_term(ErlDrvTermData port, ErlDrvTermData* term, int n)</nametext></name>
<fsummary>Send term data from driver to port owner</fsummary>
<desc>
- <marker id="driver_output_term"></marker>
+ <marker id="erl_drv_output_term"></marker>
<p>This functions sends data in the special driver term
- format. This is a fast way to deliver term data from a
- driver. It also needs no binary conversion, so the port
- owner process receives data as normal Erlang terms.</p>
+ format to the port owner process. This is a fast way to
+ deliver term data from a driver. It also needs no binary
+ conversion, so the port owner process receives data as
+ normal Erlang terms. The
+ <seealso marker="#erl_drv_send_term">erl_drv_send_term()</seealso>
+ functions can be used for sending to any arbitrary process
+ on the local node.</p>
+ <note><p>Note that the <c>port</c> parameter is <em>not</em>
+ an ordinary port handle, but a port handle converted using
+ <c>driver_mk_port()</c>.</p></note>
<p>The <c>term</c> parameter points to an array of
<c>ErlDrvTermData</c>, with <c>n</c> elements. This array
contains terms described in the driver term format. Every
term consists of one to four elements in the array. The
- term first has a term type, and then arguments.</p>
+ term first has a term type, and then arguments. The
+ <c>port</c> parameter specifies the sending port.</p>
<p>Tuple and lists (with the exception of strings, see below),
are built in reverse polish notation, so that to build a
tuple, the elements are given first, and then the tuple
@@ -1664,17 +1684,17 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len
ErlDrvPort port = ...
ErlDrvTermData spec[] = {
ERL_DRV_ATOM, driver_mk_atom("tcp"),
- ERL_DRV_PORT, driver_mk_port(port),
+ ERL_DRV_PORT, driver_mk_port(drvport),
ERL_DRV_INT, 100,
ERL_DRV_BINARY, bin, 50, 0,
ERL_DRV_LIST, 2,
ERL_DRV_TUPLE, 3,
};
- driver_output_term(port, spec, sizeof(spec) / sizeof(spec[0]));
+ erl_drv_output_term(driver_mk_port(drvport), spec, sizeof(spec) / sizeof(spec[0]));
]]>
</code>
<p>Where <c>bin</c> is a driver binary of length at least 50
- and <c>port</c> is a port handle. Note that the <c>ERL_DRV_LIST</c>
+ and <c>drvport</c> is a port handle. Note that the <c>ERL_DRV_LIST</c>
comes after the elements of the list, likewise the
<c>ERL_DRV_TUPLE</c>.</p>
<p>The term <c>ERL_DRV_STRING_CONS</c> is a way to construct
@@ -1695,7 +1715,7 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len
ERL_DRV_NIL,
ERL_DRV_LIST, 4
};
- driver_output_term(port, spec, sizeof(spec) / sizeof(spec[0]));
+ erl_drv_output_term(driver_mk_port(drvport), spec, sizeof(spec) / sizeof(spec[0]));
]]></code>
<p></p>
<code type="none"><![CDATA[
@@ -1705,7 +1725,7 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len
ERL_DRV_STRING_CONS, (ErlDrvTermData)"123", 3,
ERL_DRV_STRING_CONS, (ErlDrvTermData)"abc", 3,
};
- driver_output_term(port, spec, sizeof(spec) / sizeof(spec[0]));
+ erl_drv_output_term(driver_mk_port(drvport), spec, sizeof(spec) / sizeof(spec[0]));
]]></code>
<p>The <c>ERL_DRV_EXT2TERM</c> term type is used for passing a
term encoded with the
@@ -1725,7 +1745,7 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len
ERL_DRV_EXT2TERM, (ErlDrvTermData) binp->orig_bytes, binp->orig_size
ERL_DRV_TUPLE, 2,
};
- driver_output_term(port, spec, sizeof(spec) / sizeof(spec[0]));
+ erl_drv_output_term(driver_mk_port(drvport), spec, sizeof(spec) / sizeof(spec[0]));
]]></code>
<p>If you want to pass a binary and don't already have the content
of the binary in an <c>ErlDrvBinary</c>, you can benefit from using
@@ -1741,6 +1761,22 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len
<c>ERL_DRV_EXT2TERM</c> term types were introduced in the 5.6
version of erts.
</p>
+ <p>This function is only thread-safe when the emulator with SMP
+ support is used.</p>
+ </desc>
+ </func>
+ <func>
+ <name><ret>int</ret><nametext>driver_output_term(ErlDrvPort port, ErlDrvTermData* term, int n)</nametext></name>
+ <fsummary>Send term data from driver to port owner</fsummary>
+ <desc>
+ <marker id="driver_output_term"></marker>
+ <warning><p><c>driver_output_term()</c> is deferred and will
+ be removed in the OTP-R17 release. Use
+ <seealso marker="#erl_drv_send_term">erl_drv_output_term()</seealso>
+ instead.</p>
+ </warning>
+ <p>The parameters <c>term</c> and <c>n</c> do the same thing
+ as in <seealso marker="#erl_drv_output_term">erl_drv_output_term()</seealso>.</p>
<p>Note that this function is <em>not</em> thread-safe, not
even when the emulator with SMP support is used.</p>
</desc>
@@ -1754,6 +1790,8 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len
<c>string</c>. The atom is created and won't change, so the
return value may be saved and reused, which is faster than
looking up the atom several times.</p>
+ <p>Note that this function is <em>not</em> thread-safe, not
+ even when the emulator with SMP support is used.</p>
</desc>
</func>
<func>
@@ -1762,20 +1800,46 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len
<desc>
<marker id="driver_mk_port"></marker>
<p>This function converts a port handle to the erlang term
- format, usable in the <c>driver_output_send</c> function.</p>
+ format, usable in the <seealso marker="#erl_drv_output_term">erl_drv_output_term()</seealso>, and <seealso marker="#erl_drv_send_term">erl_drv_send_term()</seealso> functions.</p>
+ <p>Note that this function is <em>not</em> thread-safe, not
+ even when the emulator with SMP support is used.</p>
</desc>
</func>
<func>
- <name><ret>int</ret><nametext>driver_send_term(ErlDrvPort port, ErlDrvTermData receiver, ErlDrvTermData* term, int n)</nametext></name>
+ <name><ret>int</ret><nametext>erl_drv_send_term(ErlDrvTermData port, ErlDrvTermData receiver, ErlDrvTermData* term, int n)</nametext></name>
<fsummary>Send term data to other process than port owner process</fsummary>
<desc>
- <marker id="driver_send_term"></marker>
+ <marker id="erl_drv_send_term"></marker>
<p>This function is the only way for a driver to send data to
<em>other</em> processes than the port owner process. The
<c>receiver</c> parameter specifies the process to receive
the data.</p>
+ <note><p>Note that the <c>port</c> parameter is <em>not</em>
+ an ordinary port handle, but a port handle converted using
+ <c>driver_mk_port()</c>.</p></note>
+ <p>The parameters <c>port</c>, <c>term</c> and <c>n</c> do the same thing
+ as in <seealso marker="#erl_drv_output_term">erl_drv_output_term()</seealso>.</p>
+ <p>This function is only thread-safe when the emulator with SMP
+ support is used.</p>
+ </desc>
+ </func>
+ <func>
+ <name><ret>int</ret><nametext>driver_send_term(ErlDrvPort port, ErlDrvTermData receiver, ErlDrvTermData* term, int n)</nametext></name>
+ <fsummary>Send term data to other process than port owner process</fsummary>
+ <desc>
+ <marker id="driver_send_term"></marker>
+ <warning><p><c>driver_send_term()</c> is deferred and will
+ be removed in the OTP-R17 release. Use
+ <seealso marker="#erl_drv_send_term">erl_drv_send_term()</seealso>
+ instead.</p>
+ <p>Also note that parameters of <c>driver_send_term()</c>
+ cannot be properly checked by the runtime system when
+ executed by arbitrary threads. This may cause the
+ <c>driver_send_term()</c> function not to fail when
+ it should.</p>
+ </warning>
<p>The parameters <c>term</c> and <c>n</c> do the same thing
- as in <seealso marker="#driver_output_term">driver_output_term</seealso>.</p>
+ as in <seealso marker="#erl_drv_output_term">erl_drv_output_term()</seealso>.</p>
<p>This function is only thread-safe when the emulator with SMP
support is used.</p>
</desc>