diff options
Diffstat (limited to 'erts/doc/src/erl_driver.xml')
| -rw-r--r-- | erts/doc/src/erl_driver.xml | 228 |
1 files changed, 177 insertions, 51 deletions
diff --git a/erts/doc/src/erl_driver.xml b/erts/doc/src/erl_driver.xml index c055d1ca9e..34dc8af238 100644 --- a/erts/doc/src/erl_driver.xml +++ b/erts/doc/src/erl_driver.xml @@ -1,23 +1,24 @@ -<?xml version="1.0" encoding="latin1" ?> +<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE cref SYSTEM "cref.dtd"> <cref> <header> <copyright> - <year>2001</year><year>2013</year> + <year>2001</year><year>2015</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> - The contents of this file are subject to the Erlang Public License, - Version 1.1, (the "License"); you may not use this file except in - compliance with the License. You should have received a copy of the - Erlang Public License along with this software. If not, it can be - retrieved online at http://www.erlang.org/. + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 - Software distributed under the License is distributed on an "AS IS" - basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See - the License for the specific language governing rights and limitations - under the License. + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. </legalnotice> @@ -222,7 +223,7 @@ asynchronous function calls, using a thread pool provided by Erlang. There is also a select call, that can be used for asynchronous drivers.</item> - <tag><marker id="multi_threading">Multi-threading</marker></tag> + <tag><marker id="multi_threading"/>Multi-threading</tag> <item> <p>A POSIX thread like API for multi-threading is provided. The Erlang driver thread API only provide a subset of the functionality @@ -296,7 +297,7 @@ <item><p>A driver can add and later remove drivers.</p></item> <tag>Monitoring processes</tag> <item><p>A driver can monitor a process that does not own a port.</p></item> - <tag><marker id="version_management">Version management</marker></tag> + <tag><marker id="version_management"/>Version management</tag> <item> <p>Version management is enabled for drivers that have set the <seealso marker="driver_entry#extended_marker">extended_marker</seealso> @@ -315,10 +316,13 @@ <c>ERL_DRV_EXTENDED_MINOR_VERSION</c> will be incremented when new features are added. The runtime system uses the minor version of the driver to determine what features to use. - The runtime system will refuse to load a driver if the major + The runtime system will normally refuse to load a driver if the major versions differ, or if the major versions are equal and the minor version used by the driver is greater than the one used - by the runtime system.</p> + by the runtime system. Old drivers with lower major versions + will however be allowed after a bump of the major version during + a transition period of two major releases. Such old drivers might + however fail if deprecated features are used.</p> <p>The emulator will refuse to load a driver that does not use the extended driver interface, to allow for 64-bit capable drivers, @@ -343,6 +347,16 @@ the driver does not handle sizes that overflow an <c>int</c> all will work as before.</p> </item> + <tag><marker id="time_measurement"/>Time Measurement</tag> + <item><p>Support for time measurement in drivers: + <list> + <item><seealso marker="#ErlDrvTime"><c>ErlDrvTime</c></seealso></item> + <item><seealso marker="#ErlDrvTimeUnit"><c>ErlDrvTimeUnit</c></seealso></item> + <item><seealso marker="#erl_drv_monotonic_time"><c>erl_drv_monotonic_time()</c></seealso></item> + <item><seealso marker="#erl_drv_time_offset"><c>erl_drv_time_offset()</c></seealso></item> + <item><seealso marker="#erl_drv_convert_time_unit"><c>erl_drv_convert_time_unit()</c></seealso></item> + </list></p> + </item> </taglist> </section> @@ -380,12 +394,12 @@ <item> <p> Rewrite driver callback - <c><seealso marker="driver_entry#control">control</seealso></c> + <seealso marker="driver_entry#control"><c>control</c></seealso> to use return type <c>ErlDrvSSizeT</c> instead of <c>int</c>. </p> <p> Rewrite driver callback - <c><seealso marker="driver_entry#call">call</seealso></c> + <seealso marker="driver_entry#call"><c>call</c></seealso> to use return type <c>ErlDrvSSizeT</c> instead of <c>int</c>. </p> <note> @@ -403,19 +417,19 @@ <item> <p> Driver callback - <c><seealso marker="driver_entry#output">output</seealso></c> + <seealso marker="driver_entry#output"><c>output</c></seealso> now gets <c>ErlDrvSizeT</c> as 3rd argument instead of previously <c>int</c>. </p> <p> Driver callback - <c><seealso marker="driver_entry#control">control</seealso></c> + <seealso marker="driver_entry#control"><c>control</c></seealso> now gets <c>ErlDrvSizeT</c> as 4th and 6th arguments instead of previously <c>int</c>. </p> <p> Driver callback - <c><seealso marker="driver_entry#call">call</seealso></c> + <seealso marker="driver_entry#call"><c>call</c></seealso> now gets <c>ErlDrvSizeT</c> as 4th and 6th arguments instead of previously <c>int</c>. </p> @@ -543,6 +557,7 @@ typedef struct ErlDrvSysInfo { int scheduler_threads; int nif_major_version; int nif_minor_version; + int dirty_scheduler_support; } ErlDrvSysInfo; </code> @@ -607,6 +622,10 @@ typedef struct ErlDrvSysInfo { <tag><c>nif_minor_version</c></tag> <item>The value of <c>ERL_NIF_MINOR_VERSION</c> when the runtime system was compiled. </item> + <tag><c>dirty_scheduler_support</c></tag> + <item>A value <c>!= 0</c> if the runtime system has support for dirty scheduler threads; + otherwise <c>0</c>. + </item> </taglist> </item> <tag><marker id="ErlDrvBinary"/>ErlDrvBinary</tag> @@ -745,7 +764,7 @@ typedef struct ErlIOVec { created and decrement it once when the port associated with the lock terminates. The emulator will also increment the reference count when an async job is enqueued and decrement - it after an async job has been invoked, or canceled. Besides + it after an async job has been invoked. Besides this, it is the responsibility of the driver to ensure that the reference count does not reach zero before the last use of the lock by the driver has been made. The reference count @@ -851,6 +870,24 @@ typedef struct ErlIOVec { <seealso marker="#erl_drv_tsd_get">erl_drv_tsd_get()</seealso>. </p> </item> + <tag><marker id="ErlDrvTime"/>ErlDrvTime</tag> + <item> + <p>A signed 64-bit integer type for representation of time.</p> + </item> + <tag><marker id="ErlDrvTimeUnit"/>ErlDrvTimeUnit</tag> + <item> + <p>An enumeration of time units supported by the driver API:</p> + <taglist> + <tag><c>ERL_DRV_SEC</c></tag> + <item><p>Seconds</p></item> + <tag><c>ERL_DRV_MSEC</c></tag> + <item><p>Milliseconds</p></item> + <tag><c>ERL_DRV_USEC</c></tag> + <item><p>Microseconds</p></item> + <tag><c>ERL_DRV_NSEC</c></tag> + <item><p>Nanoseconds</p></item> + </taglist> + </item> </taglist> </section> @@ -1014,6 +1051,11 @@ typedef struct ErlIOVec { <fsummary>Read a system timestamp</fsummary> <desc> <marker id="driver_get_now"></marker> + <warning><p><em>This function is deprecated! Do not use it!</em> + Use <seealso marker="#erl_drv_monotonic_time"><c>erl_drv_monotonic_time()</c></seealso> + (perhaps in combination with + <seealso marker="#erl_drv_time_offset"><c>erl_drv_time_offset()</c></seealso>) + instead.</p></warning> <p>This function reads a timestamp into the memory pointed to by the parameter <c>now</c>. See the description of <seealso marker="#ErlDrvNowData">ErlDrvNowData</seealso> for specification of its fields. </p> @@ -1035,7 +1077,9 @@ typedef struct ErlIOVec { <c>select</c>/<c>poll</c> can use). On windows, the Win32 API function <c>WaitForMultipleObjects</c> is used. This places other restrictions on the event object. - Refer to the Win32 SDK documentation.</p> + Refer to the Win32 SDK documentation. + On Enea OSE, the receive function is used. See the <seealso + marker="ose:ose_erl_driver"></seealso> for more details.</p> <p>The <c>on</c> parameter should be <c>1</c> for setting events and <c>0</c> for clearing them.</p> <p>The <c>mode</c> argument is a bitwise-or combination of @@ -1047,7 +1091,7 @@ typedef struct ErlIOVec { <seealso marker="driver_entry#ready_output">ready_output</seealso>. </p> <note> - <p>Some OS (Windows) do not differentiate between read and write events. + <p>Some OS (Windows and Enea OSE) do not differentiate between read and write events. The call-back for a fired event then only depends on the value of <c>mode</c>.</p> </note> <p><c>ERL_DRV_USE</c> specifies if we are using the event object or if we want to close it. @@ -1742,15 +1786,19 @@ typedef struct ErlIOVec { term consists of one to four elements in the array. The 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), + <p>Tuples, maps 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 - term, with a count. Likewise for lists.</p> + term, with a count. Likewise for lists and maps.</p> <p>A tuple must be specified with the number of elements. (The elements precede the <c>ERL_DRV_TUPLE</c> term.)</p> <p>A list must be specified with the number of elements, including the tail, which is the last term preceding <c>ERL_DRV_LIST</c>.</p> + <p>A map must be specified with the number of key-value pairs <c>N</c>. + The key-value pairs must precede the <c>ERL_DRV_MAP</c> in this order: + <c>key1,value1,key2,value2,...,keyN,valueN</c>. + Duplicate keys are not allowed.</p> <p>The special term <c>ERL_DRV_STRING_CONS</c> is used to "splice" in a string in a list, a string given this way is not a list per se, but the elements are elements of the @@ -1774,6 +1822,7 @@ ERL_DRV_PID ErlDrvTermData pid (from driver_connected(ErlDrvPort port) ERL_DRV_STRING_CONS char *str, int len ERL_DRV_FLOAT double *dbl ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len +ERL_DRV_MAP int sz </pre> <p>The unsigned integer data type <c>ErlDrvUInt</c> and the signed integer data type <c>ErlDrvSInt</c> are 64 bits wide @@ -1856,6 +1905,24 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len }; erl_drv_output_term(driver_mk_port(drvport), spec, sizeof(spec) / sizeof(spec[0])); ]]></code> + + <p>To build the map <c>#{key1 => 100, key2 => {200, 300}}</c>, the + following call could be made.</p> + <code type="none"><![CDATA[ + ErlDrvPort port = ... + ErlDrvTermData spec[] = { + ERL_DRV_ATOM, driver_mk_atom("key1"), + ERL_DRV_INT, 100, + ERL_DRV_ATOM, driver_mk_atom("key2"), + ERL_DRV_INT, 200, + ERL_DRV_INT, 300, + ERL_DRV_TUPLE, 2, + ERL_DRV_MAP, 2 + }; + 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 <c>ERL_DRV_BUF2BINARY</c> instead of creating an <c>ErlDrvBinary</c> @@ -1995,14 +2062,13 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len <c>async_invoke</c> and <c>async_free</c>. It's typically a pointer to a structure that contains a pipe or event that can be used to signal that the async operation completed. - The data should be freed in <c>async_free</c>, because it's - called if <c>driver_async_cancel</c> is called.</p> + The data should be freed in <c>async_free</c>.</p> <p>When the async operation is done, <seealso marker="driver_entry#ready_async">ready_async</seealso> driver entry function is called. If <c>ready_async</c> is null in the driver entry, the <c>async_free</c> function is called instead.</p> - <p>The return value is a handle to the asynchronous task, which - can be used as argument to <c>driver_async_cancel</c>.</p> + <p>The return value is -1 if the <c>driver_async</c> call + fails.</p> <note> <p>As of erts version 5.5.4.3 the default stack size for threads in the async-thread pool is 16 kilowords, @@ -2040,26 +2106,6 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len </desc> </func> <func> - <name><ret>int</ret><nametext>driver_async_cancel(long id)</nametext></name> - <fsummary>Cancel an asynchronous call</fsummary> - <desc> - <marker id="driver_async_cancel"></marker> - <p>This function used to cancel a scheduled asynchronous operation, - if it was still in the queue. It returned 1 if it succeeded, and - 0 if it failed.</p> - <p>Since it could not guarantee success, it was more or less useless. - The user had to implement synchronization of cancellation anyway. - It also unnecessarily complicated the implementation. Therefore, - as of OTP-R15B <c>driver_async_cancel()</c> is deprecated, and - scheduled for removal in OTP-R17. It will currently always fail, - and return 0.</p> - <warning><p><c>driver_async_cancel()</c> is deprecated and will - be removed in the OTP-R17 release.</p> - </warning> - - </desc> - </func> - <func> <name><ret>int</ret><nametext>driver_lock_driver(ErlDrvPort port)</nametext></name> <fsummary>Make sure the driver is never unloaded</fsummary> <desc> @@ -2798,7 +2844,7 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len </func> <func> - <name><ret>int</ret><nametext>erl_drv_putenv(char *key, char *value)</nametext></name> + <name><ret>int</ret><nametext>erl_drv_putenv(const char *key, char *value)</nametext></name> <fsummary>Set the value of an environment variable</fsummary> <desc> <marker id="erl_drv_putenv"></marker> @@ -2827,7 +2873,7 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len </desc> </func> <func> - <name><ret>int</ret><nametext>erl_drv_getenv(char *key, char *value, size_t *value_size)</nametext></name> + <name><ret>int</ret><nametext>erl_drv_getenv(const char *key, char *value, size_t *value_size)</nametext></name> <fsummary>Get the value of an environment variable</fsummary> <desc> <marker id="erl_drv_getenv"></marker> @@ -2984,6 +3030,86 @@ ERL_DRV_EXT2TERM char *buf, ErlDrvUInt len </desc> </func> + <func> + <name><ret>ErlDrvTime</ret><nametext>erl_drv_monotonic_time(ErlDrvTimeUnit time_unit)</nametext></name> + <fsummary>Get Erlang Monotonic Time</fsummary> + <desc> + <marker id="erl_drv_monotonic_time"></marker> + <p>Arguments:</p> + <taglist> + <tag><c>time_unit</c></tag> + <item>Time unit of returned value.</item> + </taglist> + <p> + Returns + <seealso marker="time_correction#Erlang_Monotonic_Time">Erlang + monotonic time</seealso>. Note that it is not uncommon with + negative values. + </p> + <p>Returns <c>ERL_DRV_TIME_ERROR</c> if called with an invalid + time unit argument, or if called from a thread that is not a + scheduler thread.</p> + <p>See also:</p> + <list> + <item><seealso marker="#ErlDrvTime"><c>ErlDrvTime</c></seealso></item> + <item><seealso marker="#ErlDrvTimeUnit"><c>ErlDrvTimeUnit</c></seealso></item> + </list> + </desc> + </func> + + <func> + <name><ret>ErlDrvTime</ret><nametext>erl_drv_time_offset(ErlDrvTimeUnit time_unit)</nametext></name> + <fsummary>Get current Time Offset</fsummary> + <desc> + <marker id="erl_drv_time_offset"></marker> + <p>Arguments:</p> + <taglist> + <tag><c>time_unit</c></tag> + <item>Time unit of returned value.</item> + </taglist> + <p>Returns the current time offset between + <seealso marker="time_correction#Erlang_Monotonic_Time">Erlang monotonic time</seealso> + and + <seealso marker="time_correction#Erlang_System_Time">Erlang system time</seealso> + converted into the <c>time_unit</c> passed as argument.</p> + <p>Returns <c>ERL_DRV_TIME_ERROR</c> if called with an invalid + time unit argument, or if called from a thread that is not a + scheduler thread.</p> + <p>See also:</p> + <list> + <item><seealso marker="#ErlDrvTime"><c>ErlDrvTime</c></seealso></item> + <item><seealso marker="#ErlDrvTimeUnit"><c>ErlDrvTimeUnit</c></seealso></item> + </list> + </desc> + </func> + + <func> + <name><ret>ErlDrvTime</ret><nametext>erl_drv_convert_time_unit(ErlDrvTime val, ErlDrvTimeUnit from, ErlDrvTimeUnit to)</nametext></name> + <fsummary>Convert time unit of a time value</fsummary> + <desc> + <marker id="erl_drv_convert_time_unit"></marker> + <p>Arguments:</p> + <taglist> + <tag><c>val</c></tag> + <item>Value to convert time unit for.</item> + <tag><c>from</c></tag> + <item>Time unit of <c>val</c>.</item> + <tag><c>to</c></tag> + <item>Time unit of returned value.</item> + </taglist> + <p>Converts the <c>val</c> value of time unit <c>from</c> to + the corresponding value of time unit <c>to</c>. The result is + rounded using the floor function.</p> + <p>Returns <c>ERL_DRV_TIME_ERROR</c> if called with an invalid + time unit argument.</p> + <p>See also:</p> + <list> + <item><seealso marker="#ErlDrvTime"><c>ErlDrvTime</c></seealso></item> + <item><seealso marker="#ErlDrvTimeUnit"><c>ErlDrvTimeUnit</c></seealso></item> + </list> + </desc> + </func> + </funcs> <section> <title>SEE ALSO</title> |