aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--erts/doc/src/erlang.xml358
1 files changed, 189 insertions, 169 deletions
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 6ca57566aa..3fea64cef5 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -539,55 +539,94 @@
<name name="cancel_timer" arity="2"/>
<fsummary>Cancel a timer</fsummary>
<desc>
- <p>Cancels a timer. <c><anno>TimerRef</anno></c> needs to refer to
- a timer that was created by either
- <seealso marker="#send_after/4"><c>erlang:send_after()</c></seealso>,
- or <seealso marker="#start_timer/4"><c>erlang:start_timer()</c></seealso>.</p>
- <p>Currently available <c><anno>Option</anno>s</c>:</p>
+ <p>
+ Cancels a timer that has been created by either
+ <seealso marker="#start_timer/4"><c>erlang:start_timer()</c></seealso>,
+ or <seealso marker="#send_after/4"><c>erlang:send_after()</c></seealso>.
+ <c><anno>TimerRef</anno></c> identifies the timer, and
+ was returned by the BIF that created the timer.
+ </p>
+ <p>Currently available <c><anno>Option</anno></c>s:</p>
<taglist>
<tag><c>{async, Async}</c></tag>
<item>
- <p>Asynchronous request for cancellation. <c>Async</c>
- defaults to <c>false</c>. That is the operation will be
- performed synchronously. When <c>Async</c> is set to
- <c>true</c> the cancel operation will be performed
- asynchronously. That is, <c>cancel_timer()</c> will send
- a request for cancellation to the timer service that
- manages the timer, and then return <c>ok</c>.</p></item>
+ <p>
+ Asynchronous request for cancellation. <c>Async</c>
+ defaults to <c>false</c> which will cause the
+ cancellation to be performed synchronously. When
+ <c>Async</c> is set to <c>true</c>, the cancel
+ operation will be performed asynchronously. That is,
+ <c>erlang:cancel_timer()</c> will send an asynchronous
+ request for cancellation to the timer service that
+ manages the timer, and then return <c>ok</c>.
+ </p>
+ </item>
<tag><c>{info, Info}</c></tag>
<item>
- <p>Request information about the <c>Result</c> of the
- cancellation. <c>Info</c> defaults to <c>true</c>. That
- is information will be given. When <c>Info</c> is set to
- <c>false</c> no information about the result of the cancel
- operation will be given. When the operation is performed
- synchronously the <c>Result</c> will returned from
- <c>cancel_timer()</c>. When the operation is performed
- asynchronously, a message on the form
- <c>{cancel_timer, <anno>TimerRef</anno>, <anno>Result</anno>}</c>
- will be sent to the caller of <c>cancel_timer()</c> when
- the operation has been performed.</p></item>
+ <p>
+ Request information about the <c><anno>Result</anno></c>
+ of the cancellation. <c>Info</c> defaults to <c>true</c>
+ which means that the <c><anno>Result</anno></c> will
+ be given. When <c>Info</c> is set to <c>false</c>, no
+ information about the result of the cancellation
+ will be given. When the operation is performed</p>
+ <taglist>
+ <tag>synchronously</tag>
+ <item>
+ <p>
+ If <c>Info</c> is <c>true</c>, the <c>Result</c> will
+ returned by <c>erlang:cancel_timer()</c>; otherwise,
+ <c>ok</c> will be returned.
+ </p>
+ </item>
+ <tag>asynchronously</tag>
+ <item>
+ <p>
+ If <c>Info</c> is <c>true</c>, a message on the form
+ <c>{cancel_timer, <anno>TimerRef</anno>,
+ <anno>Result</anno>}</c> will be sent to the
+ caller of <c>erlang:cancel_timer()</c> when the
+ cancellation operation has been performed; otherwise,
+ no message will be sent.
+ </p>
+ </item>
+ </taglist>
+ </item>
</taglist>
- <p>When the <c><anno>Result</anno></c> equals <c>false</c> a timer
- corresponding to <c><anno>TimerRef</anno></c> could not be found. This
- can be either because the timer had expired, been canceled, or because
- <c><anno>TimerRef</anno></c> do not correspond to a timer. When the
- <c><anno>Result</anno></c> is an integer, it represents
- the time in milli seconds left before the timer will expire.</p>
- <note><p>The timer service that manages the timer may be co-located
- with another scheduler than the scheduler that the calling process
- is executing on. In this case communication with the timer
- service will be performed using asynchronous signals. If the calling
- process is in critical path and can do other things while waiting
- for the result of this operation, you want to use the <c>{async, true}</c>
- option.</p></note>
+ <p>
+ More <c><anno>Option</anno></c>s may be added in the future.
+ </p>
+ <p>
+ When the <c><anno>Result</anno></c> equals <c>false</c>, a
+ timer corresponding to <c><anno>TimerRef</anno></c> could not
+ be found. This can be either because the timer had expired,
+ already had been canceled, or because <c><anno>TimerRef</anno></c>
+ never has corresponded to a timer. If the timer has expired,
+ the timeout message has been sent, but it does not tell you
+ whether or not it has arrived at its destination yet. When the
+ <c><anno>Result</anno></c> is an integer, it represents the
+ time in milli-seconds left until the timer will expire.
+ </p>
+ <note>
+ <p>
+ The timer service that manages the timer may be co-located
+ with another scheduler than the scheduler that the calling
+ process is executing on. If this is the case, communication
+ with the timer service will take much longer time than if it
+ is located locally. If the calling process is in critical
+ path, and can do other things while waiting for the result
+ of this operation, or is not interested in the result of
+ the operation, you want to use the <c>{async, true}</c>
+ option. If using the <c>{async, false}</c> option, the calling
+ process will be blocked until the operation has been
+ performed.
+ </p>
+ </note>
<p>See also
<seealso marker="#send_after/4"><c>erlang:send_after/4</c></seealso>,
<seealso marker="#start_timer/4"><c>erlang:start_timer/4</c></seealso>,
and
<seealso marker="#read_timer/2"><c>erlang:read_timer/2</c></seealso>.</p>
- <p>Note: Cancelling a timer does not guarantee that the message
- has not already been delivered to the message queue.</p>
</desc>
</func>
<func>
@@ -596,7 +635,7 @@
<desc>
<p>Cancels a timer. The same as calling
<seealso marker="#cancel_timer/2"><c>erlang:cancel_timer(TimerRef,
- [{async, false}, {info, true}])</c></seealso>.</p>
+ [])</c></seealso>.</p>
</desc>
</func>
<func>
@@ -4548,37 +4587,60 @@ os_prompt% </pre>
<name name="read_timer" arity="2"/>
<fsummary>Read the state of a timer</fsummary>
<desc>
- <p>Read the state of a timer. <c><anno>TimerRef</anno></c>
- needs to refer to a timer that was created by either
- <seealso marker="#send_after/4"><c>erlang:send_after()</c></seealso>,
- or <seealso marker="#start_timer/4"><c>erlang:start_timer()</c></seealso>.</p>
+ <p>
+ Read the state of a timer that has been created by either
+ <seealso marker="#start_timer/4"><c>erlang:start_timer()</c></seealso>,
+ or <seealso marker="#send_after/4"><c>erlang:send_after()</c></seealso>.
+ <c><anno>TimerRef</anno></c> identifies the timer, and
+ was returned by the BIF that created the timer.
+ </p>
<p>Currently available <c><anno>Option</anno>s</c>:</p>
<taglist>
<tag><c>{async, Async}</c></tag>
<item>
- <p>Asynchronous request. <c>Async</c> defaults to <c>false</c>. That
- is the operation will be performed synchronously, and the <c>Result</c>
- will returned from <c>read_timer()</c>. When <c>Async</c> is set to
- <c>true</c>, <c>read_timer()</c> will send a request for the
- <c>Result</c> to a timer service that manages the timer and then
- return <c>ok</c>. A message on the format
- <c>{read_timer, <anno>TimerRef</anno>, <anno>Result</anno>}</c>
- will be sent to the caller of <c>read_timer()</c> when
- the operation has been processed.</p></item>
+ <p>
+ Asynchronous request for state information. <c>Async</c>
+ defaults to <c>false</c> which will cause the operation
+ to be performed synchronously. In this case, the <c>Result</c>
+ will be returned by <c>erlang:read_timer()</c>. When
+ <c>Async</c> is set to <c>true</c>, <c>erlang:read_timer()</c>
+ will send an asynchronous request for the state information
+ to the timer service that manages the timer, and then return
+ <c>ok</c>. A message on the format <c>{read_timer,
+ <anno>TimerRef</anno>, <anno>Result</anno>}</c> will be
+ sent to the caller of <c>erlang:read_timer()</c> when the
+ operation has been processed.
+ </p>
+ </item>
</taglist>
- <p>When the <c><anno>Result</anno></c> equals <c>false</c> a timer
- corresponding to <c><anno>TimerRef</anno></c> could not be found. This
- can be either because the timer had expired, been canceled, or because
- <c><anno>TimerRef</anno></c> do not correspond to a timer. When the
- <c><anno>Result</anno></c> is an integer, it represents
- the time in milli seconds left before the timer will expire.</p>
- <note><p>The timer service that manages the timer may be co-located
- with another scheduler than the scheduler that the calling process
- is executing on. In this case communication with the timer
- service will be performed using asynchronous signals. If the calling
- process is in critical path and can do other things while waiting
- for the result of this operation, you want to use the <c>{async, true}</c>
- option.</p></note>
+ <p>
+ More <c><anno>Option</anno></c>s may be added in the future.
+ </p>
+ <p>
+ When the <c><anno>Result</anno></c> equals <c>false</c>, a
+ timer corresponding to <c><anno>TimerRef</anno></c> could not
+ be found. This can be either because the timer had expired,
+ had been canceled, or because <c><anno>TimerRef</anno></c>
+ never has corresponded to a timer. If the timer has expired,
+ the timeout message has been sent, but it does not tell you
+ whether or not it has arrived at its destination yet. When the
+ <c><anno>Result</anno></c> is an integer, it represents the
+ time in milli-seconds left until the timer will expire.
+ </p>
+ <note>
+ <p>
+ The timer service that manages the timer may be co-located
+ with another scheduler than the scheduler that the calling
+ process is executing on. If this is the case, communication
+ with the timer service will take much longer time than if it
+ is located locally. If the calling process is in critical
+ path, and can do other things while waiting for the result
+ of this operation you want to use the <c>{async, true}</c>
+ option. If using the <c>{async, false}</c> option, the calling
+ process will be blocked until the operation has been
+ performed.
+ </p>
+ </note>
<p>See also
<seealso marker="#send_after/4"><c>erlang:send_after/4</c></seealso>,
<seealso marker="#start_timer/4"><c>erlang:start_timer/4</c></seealso>,
@@ -4592,7 +4654,7 @@ os_prompt% </pre>
<desc>
<p>Read the state of a timer. The same as calling
<seealso marker="#read_timer/2"><c>erlang:read_timer(TimerRef,
- [{async, false}])</c></seealso>.</p>
+ [])</c></seealso>.</p>
</desc>
</func>
<func>
@@ -4744,48 +4806,14 @@ true</pre>
<name name="send_after" arity="4"/>
<fsummary>Start a timer</fsummary>
<desc>
- <p>Starts a timer. When the timer expires, the message
- <c><anno>Msg</anno></c> will be sent to
- <c><anno>Dest</anno></c>.</p>
- <p>If <c><anno>Dest</anno></c> is a <c>pid()</c> it has to
- be a <c>pid()</c> of a local process, dead or alive.</p>
- <p>Currently available <c><anno>Option</anno>s</c>:</p>
- <taglist>
- <tag><c>{abs, Abs}</c></tag>
- <item>
- <p>Absolute timeout. When <c>Abs</c> is <c>false</c>
- the <c><anno>Time</anno></c> value will be interpreted
- as a time in milli-seconds relative current
- <seealso marker="time_correction#Erlang_Monotonic_Time">Erlang
- monotonic time</seealso>. When <c>Abs</c> is <c>true</c> the
- <c><anno>Time</anno></c> value will be interpreted as an absolute
- Erlang monotonic time of milli second time unit. <c>Abs</c>
- defaults to <c>false</c>.</p>
- </item>
- </taglist>
- <p>The absolute time when the timer is set to expire needs
- to be in the range between
- <seealso marker="#system_info_start_time"><c>erlang:system_info(start_time)</c></seealso>
- and
- <seealso marker="#system_info_end_time"><c>erlang:system_info(end_time)</c></seealso>.
- If a negative relative time is specified the time is not
- allowed to be negative.</p>
- <p>If <c><anno>Dest</anno></c> is an <c>atom()</c>, it is supposed to be the name of
- a registered process. The process referred to by the name is
- looked up at the time of delivery. No error is given if
- the name does not refer to a process.</p>
- <p>If <c><anno>Dest</anno></c> is a <c>pid()</c>, the timer will be automatically
- canceled if the process referred to by the <c>pid()</c> is not alive,
- or when the process exits. This feature was introduced in
- erts version 5.4.11. Note that timers will not be
- automatically canceled when <c><anno>Dest</anno></c> is an <c>atom()</c>.</p>
- <p>See also
- <seealso marker="#start_timer/4"><c>erlang:send_timer/4</c></seealso>,
- <seealso marker="#cancel_timer/2"><c>erlang:cancel_timer/2</c></seealso>,
- and
- <seealso marker="#read_timer/2"><c>erlang:read_timer/2</c></seealso>.</p>
- <p>Failure: <c>badarg</c> if the arguments does not satisfy
- the requirements specified above.</p>
+ <p>
+ Starts a timer. When the timer expires, the message
+ <c><anno>Msg</anno></c> will be sent to the process
+ identified by <c><anno>Dest</anno></c>. Appart from
+ the format of the message sent to
+ <c><anno>Dest</anno></c> when the timer expires
+ <c>erlang:send_after/4</c> works exactly as
+ <seealso marker="#start_timer/4"><c>erlang:start_timer/4</c></seealso>.</p>
</desc>
</func>
<func>
@@ -4793,36 +4821,8 @@ true</pre>
<fsummary>Start a timer</fsummary>
<desc>
<p>Starts a timer. The same as calling
- <seealso marker="#send_timer/4"><c>erlang:send_after(<anno>Time</anno>,
- <anno>Dest</anno>, <anno>Msg</anno>, [{abs, false}])</c></seealso>.</p>
- </desc>
- </func>
- <func>
- <name name="send_after" arity="3"/>
- <type_desc variable="Time">0 &lt;= Time &lt;= 4294967295</type_desc>
- <fsummary>Start a timer</fsummary>
- <desc>
- <p>Starts a timer which will send the message <c>Msg</c>
- to <c><anno>Dest</anno></c> after <c><anno>Time</anno></c> milliseconds.</p>
- <p>If <c><anno>Dest</anno></c> is a <c>pid()</c> it has to be a <c>pid()</c> of a local process, dead or alive.</p>
- <p>The <c><anno>Time</anno></c> value can, in the current implementation, not be greater than 4294967295.</p>
- <p>If <c><anno>Dest</anno></c> is an <c>atom()</c>, it is supposed to be the name of
- a registered process. The process referred to by the name is
- looked up at the time of delivery. No error is given if
- the name does not refer to a process.</p>
-
- <p>If <c><anno>Dest</anno></c> is a <c>pid()</c>, the timer will be automatically
- canceled if the process referred to by the <c>pid()</c> is not alive,
- or when the process exits. This feature was introduced in
- erts version 5.4.11. Note that timers will not be
- automatically canceled when <c><anno>Dest</anno></c> is an <c>atom</c>.</p>
- <p>See also
- <seealso marker="#start_timer/3">erlang:start_timer/3</seealso>,
- <seealso marker="#cancel_timer/2">erlang:cancel_timer/2</seealso>,
- and
- <seealso marker="#read_timer/2">erlang:read_timer/2</seealso>.</p>
- <p>Failure: <c>badarg</c> if the arguments does not satisfy
- the requirements specified above.</p>
+ <seealso marker="#send_after/4"><c>erlang:send_after(<anno>Time</anno>,
+ <anno>Dest</anno>, <anno>Msg</anno>, [])</c></seealso>.</p>
</desc>
</func>
<func>
@@ -5231,41 +5231,59 @@ true</pre>
<name name="start_timer" arity="4"/>
<fsummary>Start a timer</fsummary>
<desc>
- <p>Starts a timer. When the timer expires, the message
+ <p>
+ Starts a timer. When the timer expires, the message
<c>{timeout, <anno>TimerRef</anno>, <anno>Msg</anno>}</c>
- will be sent to <c><anno>Dest</anno></c>.</p>
- <p>If <c><anno>Dest</anno></c> is a <c>pid()</c> it has to
- be a <c>pid()</c> of a local process, dead or alive.</p>
- <p>Currently available <c><anno>Option</anno>s</c>:</p>
+ will be sent to the process identified by
+ <c><anno>Dest</anno></c>.
+ </p>
+ <p>Currently available <c><anno>Option</anno></c>s:</p>
<taglist>
<tag><c>{abs, Abs}</c></tag>
<item>
- <p>Absolute timeout. When <c>Abs</c> is <c>false</c>
- the <c><anno>Time</anno></c> value will be interpreted
- as a time in milli-seconds relative current
- <seealso marker="time_correction#Erlang_Monotonic_Time">Erlang
- monotonic time</seealso>. When <c>Abs</c> is <c>true</c> the
- <c><anno>Time</anno></c> value will be interpreted as an absolute
- Erlang monotonic time of milli second time unit. <c>Abs</c>
- defaults to <c>false</c>.</p>
+ <p>
+ Absolute <c><anno>Time</anno></c> value. <c>Abs</c>
+ defaults to <c>false</c> which means that the
+ <c><anno>Time</anno></c> value will be interpreted
+ as a time in milli-seconds relative current
+ <seealso marker="time_correction#Erlang_Monotonic_Time">Erlang
+ monotonic time</seealso>. When <c>Abs</c> is set to
+ <c>true</c>, the <c><anno>Time</anno></c> value will
+ be interpreted as an absolute Erlang monotonic time of
+ milli-seconds
+ <seealso marker="#type_time_unit">time unit</seealso>.
+ </p>
</item>
</taglist>
- <p>The absolute time when the timer is set to expire needs
- to be in the range between
- <seealso marker="#system_info_start_time"><c>erlang:system_info(start_time)</c></seealso>
- and
- <seealso marker="#system_info_end_time"><c>erlang:system_info(end_time)</c></seealso>.
- If a negative relative time is specified the time is not
- allowed to be negative.</p>
- <p>If <c><anno>Dest</anno></c> is an <c>atom()</c>, it is supposed to be the name of
- a registered process. The process referred to by the name is
- looked up at the time of delivery. No error is given if
- the name does not refer to a process.</p>
- <p>If <c><anno>Dest</anno></c> is a <c>pid()</c>, the timer will be automatically
- canceled if the process referred to by the <c>pid()</c> is not alive,
- or when the process exits. This feature was introduced in
- erts version 5.4.11. Note that timers will not be
- automatically canceled when <c><anno>Dest</anno></c> is an <c>atom()</c>.</p>
+ <p>
+ More <c><anno>Option</anno></c>s may be added in the future.
+ </p>
+ <p>
+ The absolute point in time that the timer is set to expire on
+ has to be in the interval
+ <c>[</c><seealso marker="#system_info_start_time"><c>erlang:system_info(start_time)</c></seealso><c>,
+ </c><seealso marker="#system_info_end_time"><c>erlang:system_info(end_time)</c></seealso><c>]</c>.
+ Further, if a relative time is specified, the <c><anno>Time</anno></c> value
+ is not allowed to be negative.
+ </p>
+ <p>
+ If <c><anno>Dest</anno></c> is a <c>pid()</c>, it has to
+ be a <c>pid()</c> of a process created on the current
+ runtime system instance. This process may or may not
+ have terminated. If <c><anno>Dest</anno></c> is an
+ <c>atom()</c>, it will be interpreted as the name of a
+ locally registered process. The process referred to by the
+ name is looked up at the time of timer expiration. No error
+ is given if the name does not refer to a process.
+ </p>
+ <p>
+ If <c><anno>Dest</anno></c> is a <c>pid()</c>, the timer will
+ be automatically canceled if the process referred to by the
+ <c>pid()</c> is not alive, or when the process exits. This
+ feature was introduced in erts version 5.4.11. Note that
+ timers will not be automatically canceled when
+ <c><anno>Dest</anno></c> is an <c>atom()</c>.
+ </p>
<p>See also
<seealso marker="#send_after/4"><c>erlang:send_after/4</c></seealso>,
<seealso marker="#cancel_timer/2"><c>erlang:cancel_timer/2</c></seealso>,
@@ -5281,7 +5299,7 @@ true</pre>
<desc>
<p>Starts a timer. The same as calling
<seealso marker="#start_timer/4"><c>erlang:start_timer(<anno>Time</anno>,
- <anno>Dest</anno>, <anno>Msg</anno>, [{abs, false}])</c></seealso>.</p>
+ <anno>Dest</anno>, <anno>Msg</anno>, [])</c></seealso>.</p>
</desc>
</func>
<func>
@@ -6845,7 +6863,9 @@ ok
<item><p>The <seealso marker="#monotonic_time/0">Erlang monotonic
time</seealso> in <c>native</c>
<seealso marker="#type_time_unit">time unit</seealso> at the
- time when current Erlang runtime system instance started.</p></item>
+ time when current Erlang runtime system instance started. See also
+ <seealso marker="#system_info_end_time"><c>erlang:system_info(end_time)</c></seealso>.
+ </p></item>
<tag><c>system_version</c></tag>
<item>
<p>Returns a string containing version number and