Skip to content

Commit

Permalink
Publish: Merge pull request #216 from cplusplus/LWG-feedback-2024-04-17
Browse files Browse the repository at this point in the history 
LWG feedback from 2024-04-17 a50475d
  • Loading branch information
@ericniebler
ericniebler committed May 1, 2024
1 parent b1a5288 commit e472a53
Showing 1 changed file with 38 additions and 34 deletions.
72 changes: 38 additions & 34 deletions execution.html
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2386,7 +2386,7 @@
<div class="head">
<p data-fill-with="logo"></p>
<h1 class="p-name no-ref" id="title">P2300R9<br><code class="highlight"><c- n>std</c-><c- o>::</c-><c- n>execution</c-></code></h1>
<h2 class="no-num no-toc no-ref heading settled" id="profile-and-date"><span class="content">Published Proposal, <time class="dt-updated" datetime="2024-04-17">2024-04-17</time></span></h2>
<h2 class="no-num no-toc no-ref heading settled" id="profile-and-date"><span class="content">Published Proposal, <time class="dt-updated" datetime="2024-05-01">2024-05-01</time></span></h2>
<div data-fill-with="spec-metadata">
<dl>
<dt class="editor">Authors:
Expand Down Expand Up @@ -6282,7 +6282,9 @@ <h4 class="heading settled" data-level="33.3.1" id="spec-thread.stoptoken.intro"
automatically releases the resources associated with the stop state.</del>
<li data-md>
<p>
A <code class="highlight"><c- n>stop</c-><ins><c- n>pable</c-></ins><c- n>_token</c-></code> can be passed to an operation
A
<ins>n object of a type that models</ins>
<code class="highlight"><c- n>stop</c-><ins><c- n>pable</c-></ins><c- n>_token</c-></code> can be passed to an operation
<del> which</del>
<ins>that</ins>
can either
Expand All @@ -6306,21 +6308,22 @@ <h4 class="heading settled" data-level="33.3.1" id="spec-thread.stoptoken.intro"
<p>
A stop request made via
<del>a <code class="highlight"><c- n>stop_source</c-></code></del>
<ins>an object that models <i><code class="highlight"><c- n>stoppable</c-><c- o>-</c-><c- n>source</c-></code></i></ins>
<ins>an object whose type
models <i><code class="highlight"><c- n>stoppable</c-><c- o>-</c-><c- n>source</c-></code></i></ins>
will be visible to all associated <code class="highlight"><c- n>stop</c-><ins><c- n>pable</c-></ins><c- n>_token</c-></code> and
<del><code class="highlight"><c- n>stop_source</c-></code></del>
<ins> <i><code class="highlight"><c- n>stoppable</c-><c- o>-</c-><c- n>source</c-></code></i></ins>
objects. Once a stop request has been
made it cannot be withdrawn (a subsequent stop request has no effect).
objects. Once a stop request has been made
it cannot be withdrawn (a subsequent stop request has no effect).
</p>
<li data-md>
<p>
Callbacks registered via
<del>a <code class="highlight"><c- n>stop_callback</c-></code> object</del>
<ins>an object
that models <i><code class="highlight"><c- n>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></code></i></ins>
are called when a stop
request is first made by any associated
whose type models <i><code class="highlight"><c- n>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></code></i></ins>
are called when a
stop request is first made by any associated
<del><code class="highlight"><c- n>stop_source</c-></code></del>
<ins> <i><code class="highlight"><c- n>stoppable</c-><c- o>-</c-><c- n>source</c-></code></i></ins>
object.
Expand All @@ -6342,10 +6345,11 @@ <h4 class="heading settled" data-level="33.3.1" id="spec-thread.stoptoken.intro"
The last remaining owner of the stop state automatically releases the
resources associated with the stop state.</p>
<li data-md>
<p>The types <code class="highlight"><c- n>inplace_stop_source</c-></code> and <code class="highlight"><c- n>inplace_stop_token</c-></code> and the class
template <code class="highlight"><c- n>inplace_stop_callback</c-></code> does no dynamic memory allocation of the
stop state. <span class="wg21note">They are for use when the lifetimes of
the associated token and callback objects are known to nest within the
<p>An object of type <code class="highlight"><c- n>inplace_stop_source</c-></code> is the sole owner of its stop state.
An object of type <code class="highlight"><c- n>inplace_stop_token</c-></code> or of a specialization of the class
template <code class="highlight"><c- n>inplace_stop_callback</c-></code> does not participate in ownership of its
associated stop state. <span class="wg21note">They are for use when all uses
of the associated token and callback objects are known to nest within the
lifetime of the <code class="highlight"><c- n>inplace_stop_source</c-></code> object.</span></p>
</ol>
</div>
Expand Down Expand Up @@ -6394,6 +6398,7 @@ <h4 class="heading settled" data-level="33.3.2" id="spec-thread.stoptoken.syn"><
<c- k>template</c-><c- o>&lt;</c-><c- k>class</c-> <c- nc>CallbackFn</c-><c- o>></c->
<c- k>class</c-> <c- nc>inplace_stop_callback</c-><c- p>;</c->

<span class="ed-note"><c- n>Do</c-> <c- n>we</c-> <c- n>need</c-> <c- n>the</c-> <code class="highlight"><c- o><c- o>::</c-></c-><c- k><c- k>template</c-></c-></code> <c- n>here</c-><c- o>?</c-></span>
<c- k>template</c-><c- o>&lt;</c-><c- k>class</c-> <c- nc>T</c-><c- p>,</c-> <c- k>class</c-> <c- nc>CallbackFn</c-><c- o>></c->
<c- k>using</c-> <c- n>stop_callback_for_t</c-> <c- o>=</c-> <c- n>T</c-><c- o>::</c-><c- k>template</c-> <c- n>callback_type</c-><c- o>&lt;</c-><c- n>CallbackFn</c-><c- o>></c-><c- p>;</c-></div>
<c- p>}</c->
Expand All @@ -6406,11 +6411,8 @@ <h4 class="heading settled" data-level="33.3.2" id="spec-thread.stoptoken.syn"><
<h4 class="heading settled" data-level="33.3.3" id="spec-stoptoken.concepts"><span class="secno">33.3.3. </span><span class="content">Stop token concepts <b>[stoptoken.concepts]</b></span><a class="self-link" href="#spec-stoptoken.concepts"></a></h4>
<ol>
<li data-md>
<p>For a stop token type <code class="highlight"><c- n>Token</c-></code> and a type <code class="highlight"><c- n>CallbackFn</c-></code> such that <code class="highlight"><c- n>invocable</c-><c- o>&lt;</c-><c- n>CallbackFn</c-><c- o>></c-></code> is <code class="highlight">true</code>, if the type <code class="highlight"><c- n>stop_callback_for_t</c-><c- o>&lt;</c-><c- n>Token</c-><c- p>,</c-> <c- n>CallbackFn</c-><c- o>></c-></code> is valid, it denotes the type of a
stop callback to use when registering a callback invocation to be executed
if a stop request is made on the <code class="highlight"><c- n>stoppable_token</c-></code>’s associated stop source.
The exposition-only <i><code class="highlight"><c- n>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></code></i> concept checks for a
callback compatible with a given stop token type.</p>
<p>The exposition-only <i><code class="highlight"><c- n>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></code></i> concept checks for a
callback compatible with a given <code class="highlight"><c- n>Token</c-></code> type.</p>
<pre class="highlight"><c- k>template</c-><c- o>&lt;</c-><c- k>class</c-> <c- nc>CallbackFn</c-><c- p>,</c-> <c- k>class</c-> <c- nc>Token</c-><c- p>,</c-> <c- k>class</c-> <c- nc>Initializer</c-> <c- o>=</c-> <c- n>CallbackFn</c-><c- o>></c->
<c- k>concept</c-> <i><c- nc>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></i> <c- o>=</c-> <i><c- c1>// exposition only</c-></i>
<c- n>invocable</c-><c- o>&lt;</c-><c- n>CallbackFn</c-><c- o>></c-> <c- o>&amp;&amp;</c->
Expand All @@ -6420,7 +6422,8 @@ <h4 class="heading settled" data-level="33.3.3" id="spec-stoptoken.concepts"><sp
</pre>
<li data-md>
<p>Let <code class="highlight"><c- n>t</c-></code> and <code class="highlight"><c- n>u</c-></code> be distinct, valid objects of type <code class="highlight"><c- n>Token</c-></code> that reference the
same logical stop state; let <code class="highlight"><c- n>init</c-></code> be an object of type <code class="highlight"><c- n>Initializer</c-></code>; and let <code class="highlight"><c- n>SCB</c-></code> denote the type <code class="highlight"><c- n>stop_callback_for_t</c-><c- o>&lt;</c-><c- n>Token</c-><c- p>,</c-> <c- n>CallbackFn</c-><c- o>></c-></code>.</p>
same logical stop state; let <code class="highlight"><c- n>init</c-></code> be an expression such that <code class="highlight"><c- n>same_as</c-><c- o>&lt;</c-><c- k>decltype</c-><c- p>(</c-><c- n>init</c-><c- p>),</c-> <c- n>Initializer</c-><c- o>></c-></code> is <code class="highlight">true</code>; and let <code class="highlight"><c- n>SCB</c-></code> denote the
type <code class="highlight"><c- n>stop_callback_for_t</c-><c- o>&lt;</c-><c- n>Token</c-><c- p>,</c-> <c- n>CallbackFn</c-><c- o>></c-></code>.</p>
<li data-md>
<p>The concept <code class="highlight"><i><c- n>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></i><c- o>&lt;</c-><c- n>CallbackFn</c-><c- p>,</c-> <c- n>Token</c-><c- p>,</c-> <c- n>Initializer</c-><c- o>></c-></code> is modeled only if:</p>
<ol>
Expand Down Expand Up @@ -6473,12 +6476,12 @@ <h4 class="heading settled" data-level="33.3.3" id="spec-stoptoken.concepts"><sp
</ol>
<li data-md>
<p>Destruction of <code class="highlight"><c- n>scb</c-></code> shall execute a <dfn class="dfn-paneled" data-dfn-type="dfn" data-export data-lt="stoppable callback deregistration" id="stoppable-callback-deregistration">stoppable callback
deregistration</dfn> as follows:</p>
deregistration</dfn> as follows (in order):</p>
<ol>
<li data-md>
<p>If the constructor of <code class="highlight"><c- n>scb</c-></code> did not register a callback invocation
with <code class="highlight"><c- n>t</c-></code>’s stop state, then the stoppable callback
deregistration shall have no effect.</p>
deregistration shall have no effect other than destroying <code class="highlight"><c- n>cbfn</c-></code> if it was constructed.</p>
<li data-md>
<p>Otherwise, the invocation of <code class="highlight"><c- n>cbfn</c-></code> shall be removed from
the associated stop state.</p>
Expand All @@ -6496,14 +6499,14 @@ <h4 class="heading settled" data-level="33.3.3" id="spec-stoptoken.concepts"><sp
of the invocation of some other callback registered with the same
logical stop state.</p>
<li data-md>
<p>As a final step, the stoppable callback deregistration shall destroy <code class="highlight"><c- n>cbfn</c-></code>.</p>
<p>The stoppable callback deregistration shall destroy <code class="highlight"><c- n>cbfn</c-></code>.</p>
</ol>
</ol>
<li data-md>
<p>The <code class="highlight"><c- n>stoppable_token</c-></code> concept checks for the basic interface of a stop token
that is copyable and allows polling to see if stop has been requested and
also whether a stop request is possible. The <code class="highlight"><c- n>unstoppable_token</c-></code> concept
checks for a stop token type that does not allow stopping.</p>
checks for a <code class="highlight"><c- n>stoppable_token</c-></code> type that does not allow stopping.</p>
<pre class="highlight"><c- k>template</c-><c- o>&lt;</c-><c- k>template</c-><c- o>&lt;</c-><c- k>class</c-><c- o>></c-> <c- k>class</c-><c- o>></c->
<c- k>struct</c-> <i><c- nc>check</c-><c- o>-</c-><c- n>type</c-><c- o>-</c-><c- n>alias</c-><c- o>-</c-><c- n>exists</c-></i><c- p>;</c-> <i><c- c1>// exposition-only</c-></i>

Expand All @@ -6527,25 +6530,26 @@ <h4 class="heading settled" data-level="33.3.3" id="spec-stoptoken.concepts"><sp
<c- k>requires</c-> <c- n>bool_constant</c-><c- o>&lt;</c-><c- p>(</c-><c- o>!</c-><c- n>tok</c-><c- p>.</c-><c- n>stop_possible</c-><c- p>())</c-><c- o>>::</c-><c- n>value</c-><c- p>;</c->
<c- p>};</c->
</pre>
<li data-md>
<p>An object whose type models <code class="highlight"><c- n>stoppable_token</c-></code> has at most one associated
logical stop state. A <code class="highlight"><c- n>stoppable_token</c-></code> object with no associated stop
state is said to be <dfn class="dfn-paneled" data-dfn-type="dfn" data-export id="disengaged">disengaged</dfn>.</p>
<li data-md>
<p>Let <code class="highlight"><c- n>SP</c-></code> be an evaluation of <code class="highlight"><c- n>t</c-><c- p>.</c-><c- n>stop_possible</c-><c- p>()</c-></code> that is <code class="highlight">false</code>, and let <code class="highlight"><c- n>SR</c-></code> be an evaluation of <code class="highlight"><c- n>t</c-><c- p>.</c-><c- n>stop_requested</c-><c- p>()</c-></code> that is <code class="highlight">true</code>.</p>
<li data-md>
<p>The type <code class="highlight"><c- n>Token</c-></code> models <code class="highlight"><c- n>stoppable_token</c-></code> only if:</p>
<ol>
<li data-md>
<p>An evaluation, <code class="highlight"><c- n>E</c-></code>, of <code class="highlight"><c- n>t</c-><c- p>.</c-><c- n>stop_possible</c-><c- p>()</c-></code> is <code class="highlight">false</code>, then
evaluations of <code class="highlight"><c- n>u</c-><c- p>.</c-><c- n>stop_possible</c-><c- p>()</c-></code> and <code class="highlight"><c- n>u</c-><c- p>.</c-><c- n>stop_requested</c-><c- p>()</c-></code> that happen
after <code class="highlight"><c- n>E</c-></code> shall evaluate to <code class="highlight">false</code>.</p>
<p>Any evaluation of <code class="highlight"><c- n>u</c-><c- p>.</c-><c- n>stop_possible</c-><c- p>()</c-></code> or <code class="highlight"><c- n>u</c-><c- p>.</c-><c- n>stop_requested</c-><c- p>()</c-></code> that happens after ([intro.races]) <code class="highlight"><c- n>SP</c-></code> is <code class="highlight">false</code>.</p>
<li data-md>
<p>An evaluation, <code class="highlight"><c- n>E</c-></code>, of <code class="highlight"><c- n>t</c-><c- p>.</c-><c- n>stop_requested</c-><c- p>()</c-></code> is <code class="highlight">true</code>, then
evaluations of <code class="highlight"><c- n>u</c-><c- p>.</c-><c- n>stop_possible</c-><c- p>()</c-></code> and <code class="highlight"><c- n>u</c-><c- p>.</c-><c- n>stop_requested</c-><c- p>()</c-></code> that happen
after <code class="highlight"><c- n>E</c-></code> shall evaluate to <code class="highlight">true</code>.</p>
<p>Any evaluation of <code class="highlight"><c- n>u</c-><c- p>.</c-><c- n>stop_possible</c-><c- p>()</c-></code> or <code class="highlight"><c- n>u</c-><c- p>.</c-><c- n>stop_requested</c-><c- p>()</c-></code> that happens after <code class="highlight"><c- n>SR</c-></code> is <code class="highlight">true</code>.</p>
<li data-md>
<p>For any types <code class="highlight"><c- n>CallbackFn</c-></code> and <code class="highlight"><c- n>Initializer</c-></code>, if <code class="highlight"><i><c- n>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></i><c- o>&lt;</c-><c- n>CallbackFn</c-><c- p>,</c-> <c- n>Token</c-><c- p>,</c-> <c- n>Initializer</c-><c- o>></c-></code> is satisfied, then <code class="highlight"><i><c- n>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></i><c- o>&lt;</c-><c- n>CallbackFn</c-><c- p>,</c-> <c- n>Token</c-><c- p>,</c-> <c- n>Initializer</c-><c- o>></c-></code> shall be modeled.</p>
<p>For any types <code class="highlight"><c- n>CallbackFn</c-></code> and <code class="highlight"><c- n>Initializer</c-></code> such that <code class="highlight"><i><c- n>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></i><c- o>&lt;</c-><c- n>CallbackFn</c-><c- p>,</c-> <c- n>Token</c-><c- p>,</c-> <c- n>Initializer</c-><c- o>></c-></code> is satisfied, <code class="highlight"><i><c- n>stoppable</c-><c- o>-</c-><c- n>callback</c-><c- o>-</c-><c- k>for</c-></i><c- o>&lt;</c-><c- n>CallbackFn</c-><c- p>,</c-> <c- n>Token</c-><c- p>,</c-> <c- n>Initializer</c-><c- o>></c-></code> is modeled.</p>
<li data-md>
<p>An object that models <code class="highlight"><c- n>stoppable_token</c-></code> has at most one associated
logical stop state. A <code class="highlight"><c- n>stoppable_token</c-></code> object with no associated stop
state is said to be <dfn class="dfn-paneled" data-dfn-type="dfn" data-export id="disengaged">disengaged</dfn>. For a disengaged <code class="highlight"><c- n>stoppable_token</c-></code> object, <code class="highlight"><c- n>stop_possible</c-></code> and <code class="highlight"><c- n>stop_requested</c-></code> shall
return <code class="highlight">false</code>. If <code class="highlight"><c- n>t</c-></code> and <code class="highlight"><c- n>u</c-></code> reference the same stop state, or if both <code class="highlight"><c- n>t</c-></code> and <code class="highlight"><c- n>u</c-></code> are disengaged, <code class="highlight"><c- n>t</c-> <c- o>==</c-> <c- n>u</c-></code> shall be <code class="highlight">true</code>; otherwise, it
shall be <code class="highlight">false</code>.</p>
<p>If <code class="highlight"><c- n>t</c-></code> is disengaged, evaluations of <code class="highlight"><c- n>t</c-><c- p>.</c-><c- n>stop_possible</c-><c- p>()</c-></code> and <code class="highlight"><c- n>t</c-><c- p>.</c-><c- n>stop_requested</c-><c- p>()</c-></code> are <code class="highlight">false</code>.</p>
<li data-md>
<p>If <code class="highlight"><c- n>t</c-></code> and <code class="highlight"><c- n>u</c-></code> reference the same stop state, or if both <code class="highlight"><c- n>t</c-></code> and <code class="highlight"><c- n>u</c-></code> are
disengaged, <code class="highlight"><c- n>t</c-> <c- o>==</c-> <c- n>u</c-></code> is <code class="highlight">true</code>; otherwise, it is <code class="highlight">false</code>.</p>
</ol>
<li data-md>
<p>An object whose type models the exposition-only <i><code class="highlight"><c- n>stoppable</c-><c- o>-</c-><c- n>source</c-></code></i> concept can be queried whether stop has been requested (<code class="highlight"><c- n>stop_requested</c-></code>)
Expand Down

0 comments on commit e472a53

Please sign in to comment.