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24 | </div> | |
25 | <div class="section"> | |
26 | <div class="titlepage"><div><div><h2 class="title" style="clear: both"> | |
27 | <a name="context.ecv2_class"></a><a name="ecv2"></a><a class="link" href="ecv2_class.html" title="Class execution_context (version 2)">Class execution_context | |
28 | (version 2)</a> | |
29 | </h2></div></div></div> | |
30 | <div class="note"><table border="0" summary="Note"> | |
31 | <tr> | |
32 | <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td> | |
33 | <th align="left">Note</th> | |
34 | </tr> | |
35 | <tr><td align="left" valign="top"><p> | |
36 | This class is enabled per default. | |
37 | </p></td></tr> | |
38 | </table></div> | |
39 | <p> | |
40 | Class <span class="emphasis"><em>execution_context</em></span> encapsulates context switching | |
41 | and manages the associated context' stack (allocation/deallocation). | |
42 | </p> | |
43 | <p> | |
44 | <span class="emphasis"><em>execution_context</em></span> allocates the context stack (using its | |
45 | <a class="link" href="stack.html#stack"><span class="emphasis"><em>StackAllocator</em></span></a> argument) | |
46 | and creates a control structure on top of it. This structure is responsible | |
47 | for managing context' stack. The address of the control structure is stored | |
48 | in the first frame of context' stack (e.g. it can not directly accessed from | |
49 | within <span class="emphasis"><em>execution_context</em></span>). In contrast to <a class="link" href="ecv1_class.html#ecv1"><span class="emphasis"><em>execution_context</em></span> | |
50 | (v1)</a> the ownership of the control structure is not shared (no member | |
51 | variable to control structure in <span class="emphasis"><em>execution_context</em></span>). | |
52 | <span class="emphasis"><em>execution_context</em></span> keeps internally a state that is moved | |
53 | by a call of <span class="emphasis"><em>execution_context::operator()</em></span> (<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> will be | |
54 | invalidated), e.g. after a calling <span class="emphasis"><em>execution_context::operator()</em></span>, | |
55 | <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> | |
56 | can not be used for an additional context switch. | |
57 | </p> | |
58 | <p> | |
59 | <span class="emphasis"><em>execution_context</em></span> is only move-constructible and move-assignable. | |
60 | </p> | |
61 | <p> | |
62 | The moved state is assigned to a new instance of <span class="emphasis"><em>execution_context</em></span>. | |
63 | This object becomes the first argument of the context-function, if the context | |
64 | was resumed the first time, or the first element in a tuple returned by <span class="emphasis"><em>execution_context::operator()</em></span> | |
65 | that has been called in the resumed context. In contrast to <a class="link" href="ecv1_class.html#ecv1"><span class="emphasis"><em>execution_context</em></span> | |
66 | (v1)</a>, the context switch is faster because no global pointer etc. is | |
67 | involved. | |
68 | </p> | |
69 | <div class="important"><table border="0" summary="Important"> | |
70 | <tr> | |
71 | <td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../doc/src/images/important.png"></td> | |
72 | <th align="left">Important</th> | |
73 | </tr> | |
74 | <tr><td align="left" valign="top"><p> | |
75 | Segmented stacks are not supported by <span class="emphasis"><em>execution_context</em></span> | |
76 | (v2). | |
77 | </p></td></tr> | |
78 | </table></div> | |
79 | <p> | |
80 | On return the context-function of the current context has to specify an <span class="emphasis"><em>execution_context</em></span> | |
81 | to which the execution cotnrol is transferred after termination of the current | |
82 | context. | |
83 | </p> | |
84 | <p> | |
85 | If an instance with valid state goes out of scope and the context-function | |
86 | has not yet returned, the stack is traversed in order to access the control | |
87 | structure (address stored at the first stack frame) and to deallocate context' | |
88 | stack via the <span class="emphasis"><em>StackAllocator</em></span>. The stack walking makes | |
89 | the destruction of <span class="emphasis"><em>execution_context</em></span> very slow and should | |
90 | be prevented if possible. | |
91 | </p> | |
92 | <p> | |
93 | <span class="emphasis"><em>execution_context</em></span> expects a function/functor with signature | |
94 | <code class="computeroutput"><span class="identifier">execution_context</span><span class="special">(</span><span class="identifier">execution_context</span> <span class="identifier">ctx</span><span class="special">,</span> <span class="keyword">void</span><span class="special">*</span> | |
95 | <span class="identifier">vp</span><span class="special">)</span></code>. | |
96 | The parameter <code class="computeroutput"><span class="identifier">ctx</span></code> represents | |
97 | the context from which this context was resumed (e.g. that has called <span class="emphasis"><em>execution_context::operator()</em></span> | |
98 | on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>) | |
99 | and <code class="computeroutput"><span class="identifier">vp</span></code> is the data passed to | |
100 | <span class="emphasis"><em>execution_context::operator()</em></span>. The return value is the | |
101 | execution_context that has to be resumed, while this context terminates. | |
102 | </p> | |
103 | <h4> | |
104 | <a name="context.ecv2_class.h0"></a> | |
105 | <span><a name="context.ecv2_class.usage_of__emphasis_execution_context__emphasis_"></a></span><a class="link" href="ecv2_class.html#context.ecv2_class.usage_of__emphasis_execution_context__emphasis_">usage | |
106 | of <span class="emphasis"><em>execution_context</em></span></a> | |
107 | </h4> | |
108 | <pre class="programlisting"><span class="keyword">int</span> <span class="identifier">n</span><span class="special">=</span><span class="number">35</span><span class="special">;</span> | |
109 | <span class="identifier">ctx</span><span class="special">::</span><span class="identifier">execution_context</span> <span class="identifier">source</span><span class="special">(</span> | |
110 | <span class="special">[</span><span class="identifier">n</span><span class="special">](</span><span class="identifier">ctx</span><span class="special">::</span><span class="identifier">execution_context</span> <span class="identifier">sink</span><span class="special">,</span><span class="keyword">void</span><span class="special">*)</span><span class="keyword">mutable</span><span class="special">{</span> | |
111 | <span class="keyword">int</span> <span class="identifier">a</span><span class="special">=</span><span class="number">0</span><span class="special">;</span> | |
112 | <span class="keyword">int</span> <span class="identifier">b</span><span class="special">=</span><span class="number">1</span><span class="special">;</span> | |
113 | <span class="keyword">while</span><span class="special">(</span><span class="identifier">n</span><span class="special">--></span><span class="number">0</span><span class="special">){</span> | |
114 | <span class="keyword">auto</span> <span class="identifier">result</span><span class="special">=</span><span class="identifier">sink</span><span class="special">(&</span><span class="identifier">a</span><span class="special">);</span> | |
115 | <span class="identifier">sink</span><span class="special">=</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">0</span><span class="special">>(</span><span class="identifier">result</span><span class="special">));</span> | |
116 | <span class="keyword">auto</span> <span class="identifier">next</span><span class="special">=</span><span class="identifier">a</span><span class="special">+</span><span class="identifier">b</span><span class="special">;</span> | |
117 | <span class="identifier">a</span><span class="special">=</span><span class="identifier">b</span><span class="special">;</span> | |
118 | <span class="identifier">b</span><span class="special">=</span><span class="identifier">next</span><span class="special">;</span> | |
119 | <span class="special">}</span> | |
120 | <span class="keyword">return</span> <span class="identifier">sink</span><span class="special">;</span> | |
121 | <span class="special">});</span> | |
122 | <span class="keyword">for</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span><span class="special">=</span><span class="number">0</span><span class="special">;</span><span class="identifier">i</span><span class="special"><</span><span class="number">10</span><span class="special">;++</span><span class="identifier">i</span><span class="special">){</span> | |
123 | <span class="keyword">auto</span> <span class="identifier">result</span><span class="special">=</span><span class="identifier">source</span><span class="special">();</span> | |
124 | <span class="identifier">source</span><span class="special">=</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">0</span><span class="special">>(</span><span class="identifier">result</span><span class="special">));</span> | |
125 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span><span class="special"><<*(</span><span class="keyword">int</span><span class="special">*)</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">1</span><span class="special">>(</span><span class="identifier">result</span><span class="special">)<<</span><span class="string">" "</span><span class="special">;</span> | |
126 | <span class="special">}</span> | |
127 | ||
128 | <span class="identifier">output</span><span class="special">:</span> | |
129 | <span class="number">0</span> <span class="number">1</span> <span class="number">1</span> <span class="number">2</span> <span class="number">3</span> <span class="number">5</span> <span class="number">8</span> <span class="number">13</span> <span class="number">21</span> <span class="number">34</span> | |
130 | </pre> | |
131 | <p> | |
132 | This simple example demonstrates the basic usage of <span class="emphasis"><em>execution_context</em></span>. | |
133 | The context <code class="computeroutput"><span class="identifier">sink</span></code> represents | |
134 | the <span class="emphasis"><em>main</em></span>-context (function <span class="emphasis"><em>main()</em></span> | |
135 | running). <code class="computeroutput"><span class="identifier">sink</span></code> is generated | |
136 | by the framework (first element of lambda's parameter list). Because the state | |
137 | is invalidated (== changed) by each call of <span class="emphasis"><em>execution_context::operator()</em></span>, | |
138 | <code class="computeroutput"><span class="identifier">sink</span></code> has to be assigned the | |
139 | new state of the <span class="emphasis"><em>execution_context</em></span> returned by <span class="emphasis"><em>execution_context::operator()</em></span>. | |
140 | </p> | |
141 | <p> | |
142 | The lambda that calculates the Fibonacci numbers is executed inside the context | |
143 | represented by <code class="computeroutput"><span class="identifier">source</span></code>. Calculated | |
144 | Fibonacci numbers are transferred between the two context' via expression | |
145 | <span class="emphasis"><em>sink(&a)</em></span> (and returned by <span class="emphasis"><em>source()</em></span>). | |
146 | </p> | |
147 | <p> | |
148 | The locale variables <code class="computeroutput"><span class="identifier">a</span></code>, <code class="computeroutput"><span class="identifier">b</span></code> and <code class="computeroutput"> <span class="identifier">next</span></code> | |
149 | remain their values during each context switch (<span class="emphasis"><em>yield(a)</em></span>). | |
150 | This is possible due <code class="computeroutput"><span class="identifier">ctx</span></code> has | |
151 | its own stack and the stack is exchanged by each context switch. | |
152 | </p> | |
153 | <h4> | |
154 | <a name="context.ecv2_class.h1"></a> | |
155 | <span><a name="context.ecv2_class.inverting_the_control_flow"></a></span><a class="link" href="ecv2_class.html#context.ecv2_class.inverting_the_control_flow">inverting | |
156 | the control flow</a> | |
157 | </h4> | |
158 | <pre class="programlisting"><span class="comment">/* | |
159 | * grammar: | |
160 | * P ---> E '\0' | |
161 | * E ---> T {('+'|'-') T} | |
162 | * T ---> S {('*'|'/') S} | |
163 | * S ---> digit | '(' E ')' | |
164 | */</span> | |
165 | <span class="keyword">class</span> <span class="identifier">Parser</span><span class="special">{</span> | |
166 | <span class="comment">// implementation omitted; see examples directory</span> | |
167 | <span class="special">};</span> | |
168 | ||
169 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">istringstream</span> <span class="identifier">is</span><span class="special">(</span><span class="string">"1+1"</span><span class="special">);</span> | |
170 | <span class="keyword">bool</span> <span class="identifier">done</span><span class="special">=</span><span class="keyword">false</span><span class="special">;</span> | |
171 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">exception_ptr</span> <span class="identifier">except</span><span class="special">;</span> | |
172 | ||
173 | <span class="comment">// execute parser in new execution context</span> | |
174 | <span class="identifier">boost</span><span class="special">::</span><span class="identifier">context</span><span class="special">::</span><span class="identifier">execution_context</span> <span class="identifier">source</span><span class="special">(</span> | |
175 | <span class="special">[&</span><span class="identifier">is</span><span class="special">,&</span><span class="identifier">done</span><span class="special">,&</span><span class="identifier">except</span><span class="special">](</span><span class="identifier">ctx</span><span class="special">::</span><span class="identifier">execution_context</span> <span class="identifier">sink</span><span class="special">,</span><span class="keyword">void</span><span class="special">*){</span> | |
176 | <span class="comment">// create parser with callback function</span> | |
177 | <span class="identifier">Parser</span> <span class="identifier">p</span><span class="special">(</span> <span class="identifier">is</span><span class="special">,</span> | |
178 | <span class="special">[&</span><span class="identifier">sink</span><span class="special">](</span><span class="keyword">char</span> <span class="identifier">ch</span><span class="special">){</span> | |
179 | <span class="comment">// resume main execution context</span> | |
180 | <span class="keyword">auto</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">sink</span><span class="special">(&</span><span class="identifier">ch</span><span class="special">);</span> | |
181 | <span class="identifier">sink</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">0</span><span class="special">>(</span><span class="identifier">result</span><span class="special">));</span> | |
182 | <span class="special">});</span> | |
183 | <span class="keyword">try</span> <span class="special">{</span> | |
184 | <span class="comment">// start recursive parsing</span> | |
185 | <span class="identifier">p</span><span class="special">.</span><span class="identifier">run</span><span class="special">();</span> | |
186 | <span class="special">}</span> <span class="keyword">catch</span> <span class="special">(...)</span> <span class="special">{</span> | |
187 | <span class="comment">// store other exceptions in exception-pointer</span> | |
188 | <span class="identifier">except</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">current_exception</span><span class="special">();</span> | |
189 | <span class="special">}</span> | |
190 | <span class="comment">// set termination flag</span> | |
191 | <span class="identifier">done</span><span class="special">=</span><span class="keyword">true</span><span class="special">;</span> | |
192 | <span class="comment">// resume main execution context</span> | |
193 | <span class="keyword">return</span> <span class="identifier">sink</span><span class="special">;</span> | |
194 | <span class="special">});</span> | |
195 | ||
196 | <span class="comment">// user-code pulls parsed data from parser</span> | |
197 | <span class="comment">// invert control flow</span> | |
198 | <span class="keyword">auto</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">source</span><span class="special">();</span> | |
199 | <span class="identifier">source</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">0</span><span class="special">>(</span><span class="identifier">result</span><span class="special">));</span> | |
200 | <span class="keyword">void</span> <span class="special">*</span> <span class="identifier">vp</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">1</span><span class="special">>(</span><span class="identifier">result</span><span class="special">);</span> | |
201 | <span class="keyword">if</span> <span class="special">(</span> <span class="identifier">except</span><span class="special">)</span> <span class="special">{</span> | |
202 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">rethrow_exception</span><span class="special">(</span><span class="identifier">except</span><span class="special">);</span> | |
203 | <span class="special">}</span> | |
204 | <span class="keyword">while</span><span class="special">(</span> <span class="special">!</span> <span class="identifier">done</span><span class="special">)</span> <span class="special">{</span> | |
205 | <span class="identifier">printf</span><span class="special">(</span><span class="string">"Parsed: %c\n"</span><span class="special">,*</span> <span class="keyword">static_cast</span><span class="special"><</span><span class="keyword">char</span><span class="special">*>(</span><span class="identifier">vp</span><span class="special">));</span> | |
206 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">tie</span><span class="special">(</span><span class="identifier">source</span><span class="special">,</span><span class="identifier">vp</span><span class="special">)</span> <span class="special">=</span> <span class="identifier">source</span><span class="special">();</span> | |
207 | <span class="keyword">if</span> <span class="special">(</span><span class="identifier">except</span><span class="special">)</span> <span class="special">{</span> | |
208 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">rethrow_exception</span><span class="special">(</span><span class="identifier">except</span><span class="special">);</span> | |
209 | <span class="special">}</span> | |
210 | <span class="special">}</span> | |
211 | ||
212 | <span class="identifier">output</span><span class="special">:</span> | |
213 | <span class="identifier">Parsed</span><span class="special">:</span> <span class="number">1</span> | |
214 | <span class="identifier">Parsed</span><span class="special">:</span> <span class="special">+</span> | |
215 | <span class="identifier">Parsed</span><span class="special">:</span> <span class="number">1</span> | |
216 | </pre> | |
217 | <p> | |
218 | In this example a recursive descent parser uses a callback to emit a newly | |
219 | passed symbol. Using <span class="emphasis"><em>execution_context</em></span> the control flow | |
220 | can be inverted, e.g. the user-code pulls parsed symbols from the parser - | |
221 | instead to get pushed from the parser (via callback). | |
222 | </p> | |
223 | <p> | |
224 | The data (character) is transferred between the two <span class="emphasis"><em>execution_context</em></span>. | |
225 | </p> | |
226 | <p> | |
227 | If the code executed by <span class="emphasis"><em>execution_context</em></span> emits an exception, | |
228 | the application is terminated. <span class="emphasis"><em>std::exception_ptr</em></span> can | |
229 | be used to transfer exceptions between different execution contexts. | |
230 | </p> | |
231 | <p> | |
232 | Sometimes it is necessary to unwind the stack of an unfinished context to destroy | |
233 | local stack variables so they can release allocated resources (RAII pattern). | |
234 | The user is responsible for this task. | |
235 | </p> | |
236 | <a name="ecv2_prealloc"></a><h4> | |
237 | <a name="context.ecv2_class.h2"></a> | |
238 | <span><a name="context.ecv2_class.allocating_control_structures_on_top_of_stack"></a></span><a class="link" href="ecv2_class.html#context.ecv2_class.allocating_control_structures_on_top_of_stack">allocating | |
239 | control structures on top of stack</a> | |
240 | </h4> | |
241 | <p> | |
242 | Allocating control structures on top of the stack requires to allocated the | |
243 | <span class="emphasis"><em>stack_context</em></span> and create the control structure with placement | |
244 | new before <span class="emphasis"><em>execution_context</em></span> is created. | |
245 | </p> | |
246 | <div class="note"><table border="0" summary="Note"> | |
247 | <tr> | |
248 | <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td> | |
249 | <th align="left">Note</th> | |
250 | </tr> | |
251 | <tr><td align="left" valign="top"><p> | |
252 | The user is responsible for destructing the control structure at the top | |
253 | of the stack. | |
254 | </p></td></tr> | |
255 | </table></div> | |
256 | <pre class="programlisting"><span class="comment">// stack-allocator used for (de-)allocating stack</span> | |
257 | <span class="identifier">fixedsize_stack</span> <span class="identifier">salloc</span><span class="special">(</span> <span class="number">4048</span><span class="special">);</span> | |
258 | <span class="comment">// allocate stack space</span> | |
259 | <span class="identifier">stack_context</span> <span class="identifier">sctx</span><span class="special">(</span> <span class="identifier">salloc</span><span class="special">.</span><span class="identifier">allocate</span><span class="special">()</span> <span class="special">);</span> | |
260 | <span class="comment">// reserve space for control structure on top of the stack</span> | |
261 | <span class="keyword">void</span> <span class="special">*</span> <span class="identifier">sp</span> <span class="special">=</span> <span class="keyword">static_cast</span><span class="special"><</span> <span class="keyword">char</span> <span class="special">*</span> <span class="special">>(</span> <span class="identifier">sctx</span><span class="special">.</span><span class="identifier">sp</span><span class="special">)</span> <span class="special">-</span> <span class="keyword">sizeof</span><span class="special">(</span> <span class="identifier">my_control_structure</span><span class="special">);</span> | |
262 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span> <span class="special">=</span> <span class="identifier">sctx</span><span class="special">.</span><span class="identifier">size</span> <span class="special">-</span> <span class="keyword">sizeof</span><span class="special">(</span> <span class="identifier">my_control_structure</span><span class="special">);</span> | |
263 | <span class="comment">// placement new creates control structure on reserved space</span> | |
264 | <span class="identifier">my_control_structure</span> <span class="special">*</span> <span class="identifier">cs</span> <span class="special">=</span> <span class="keyword">new</span> <span class="special">(</span> <span class="identifier">sp</span><span class="special">)</span> <span class="identifier">my_control_structure</span><span class="special">(</span> <span class="identifier">sp</span><span class="special">,</span> <span class="identifier">size</span><span class="special">,</span> <span class="identifier">sctx</span><span class="special">,</span> <span class="identifier">salloc</span><span class="special">);</span> | |
265 | <span class="special">...</span> | |
266 | <span class="comment">// destructing the control structure</span> | |
267 | <span class="identifier">cs</span><span class="special">->~</span><span class="identifier">my_control_structure</span><span class="special">();</span> | |
268 | <span class="special">...</span> | |
269 | <span class="keyword">struct</span> <span class="identifier">my_control_structure</span> <span class="special">{</span> | |
270 | <span class="comment">// captured context</span> | |
271 | <span class="identifier">execution_context</span> <span class="identifier">cctx</span><span class="special">;</span> | |
272 | ||
273 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">StackAllocator</span> <span class="special">></span> | |
274 | <span class="identifier">my_control_structure</span><span class="special">(</span> <span class="keyword">void</span> <span class="special">*</span> <span class="identifier">sp</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">,</span> <span class="identifier">stack_context</span> <span class="identifier">sctx</span><span class="special">,</span> <span class="identifier">StackAllocator</span> <span class="identifier">salloc</span><span class="special">)</span> <span class="special">:</span> | |
275 | <span class="comment">// create captured context</span> | |
276 | <span class="identifier">cctx</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator_arg</span><span class="special">,</span> <span class="identifier">preallocated</span><span class="special">(</span> <span class="identifier">sp</span><span class="special">,</span> <span class="identifier">size</span><span class="special">,</span> <span class="identifier">sctx</span><span class="special">),</span> <span class="identifier">salloc</span><span class="special">,</span> <span class="identifier">entry_func</span><span class="special">)</span> <span class="special">{</span> | |
277 | <span class="special">}</span> | |
278 | <span class="special">...</span> | |
279 | <span class="special">};</span> | |
280 | </pre> | |
281 | <h4> | |
282 | <a name="context.ecv2_class.h3"></a> | |
283 | <span><a name="context.ecv2_class.exception_handling"></a></span><a class="link" href="ecv2_class.html#context.ecv2_class.exception_handling">exception | |
284 | handling</a> | |
285 | </h4> | |
286 | <p> | |
287 | If the function executed inside a <span class="emphasis"><em>execution_context</em></span> emits | |
288 | ans exception, the application is terminated by calling <span class="emphasis"><em>std::terminate()</em></span>. | |
289 | <span class="emphasis"><em>std::exception_ptr</em></span> can be used to transfer exceptions | |
290 | between different execution contexts. | |
291 | </p> | |
292 | <h4> | |
293 | <a name="context.ecv2_class.h4"></a> | |
294 | <span><a name="context.ecv2_class.parameter_passing"></a></span><a class="link" href="ecv2_class.html#context.ecv2_class.parameter_passing">parameter | |
295 | passing</a> | |
296 | </h4> | |
297 | <p> | |
298 | The void pointer argument passed to <span class="emphasis"><em>execution_context::operator()</em></span>, | |
299 | in one context, is passed as the last argument of the <span class="emphasis"><em>context-function</em></span> | |
300 | if the context is started for the first time. In all following invocations | |
301 | of <span class="emphasis"><em>execution_context::operator()</em></span> the void pointer passed | |
302 | to <span class="emphasis"><em>execution_context::operator()</em></span>, in one context, is returned | |
303 | by <span class="emphasis"><em>execution_context::operator()</em></span> in the other context. | |
304 | </p> | |
305 | <pre class="programlisting"><span class="keyword">class</span> <span class="identifier">X</span> <span class="special">{</span> | |
306 | <span class="keyword">private</span><span class="special">:</span> | |
307 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">exception_ptr</span> <span class="identifier">excptr_</span><span class="special">;</span> | |
308 | <span class="identifier">boost</span><span class="special">::</span><span class="identifier">context</span><span class="special">::</span><span class="identifier">execution_context</span> <span class="identifier">ctx_</span><span class="special">;</span> | |
309 | ||
310 | <span class="keyword">public</span><span class="special">:</span> | |
311 | <span class="identifier">X</span><span class="special">()</span> <span class="special">:</span> | |
312 | <span class="identifier">excptr_</span><span class="special">(),</span> | |
313 | <span class="identifier">ctx_</span><span class="special">([=](</span><span class="identifier">ctx</span><span class="special">::</span><span class="identifier">execution_context</span> <span class="identifier">ctx</span><span class="special">,</span> <span class="keyword">void</span><span class="special">*</span> <span class="identifier">vp</span><span class="special">)</span><span class="keyword">mutable</span><span class="special">{</span> | |
314 | <span class="keyword">try</span> <span class="special">{</span> | |
315 | <span class="keyword">for</span> <span class="special">(;;)</span> <span class="special">{</span> | |
316 | <span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="special">*</span> <span class="keyword">static_cast</span><span class="special"><</span><span class="keyword">int</span><span class="special">*>(</span><span class="identifier">vp</span><span class="special">);</span> | |
317 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">str</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">>(</span><span class="identifier">i</span><span class="special">);</span> | |
318 | <span class="keyword">auto</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">ctx</span><span class="special">(&</span> <span class="identifier">str</span><span class="special">);</span> | |
319 | <span class="identifier">ctx</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">0</span><span class="special">>(</span><span class="identifier">result</span><span class="special">)</span> <span class="special">);</span> | |
320 | <span class="identifier">vp</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">1</span><span class="special">>(</span><span class="identifier">result</span><span class="special">);</span> | |
321 | <span class="special">}</span> | |
322 | <span class="special">}</span> <span class="keyword">catch</span> <span class="special">(</span><span class="identifier">ctx</span><span class="special">::</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">forced_unwind</span> <span class="keyword">const</span><span class="special">&)</span> <span class="special">{</span> | |
323 | <span class="keyword">throw</span><span class="special">;</span> | |
324 | <span class="special">}</span> <span class="keyword">catch</span> <span class="special">(...)</span> <span class="special">{</span> | |
325 | <span class="identifier">excptr_</span><span class="special">=</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">current_exception</span><span class="special">();</span> | |
326 | <span class="special">}</span> | |
327 | <span class="keyword">return</span> <span class="identifier">ctx</span><span class="special">;</span> | |
328 | <span class="special">})</span> | |
329 | <span class="special">{}</span> | |
330 | ||
331 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="keyword">operator</span><span class="special">()(</span><span class="keyword">int</span> <span class="identifier">i</span><span class="special">)</span> <span class="special">{</span> | |
332 | <span class="keyword">auto</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">ctx_</span><span class="special">(&</span><span class="identifier">i</span><span class="special">);</span> | |
333 | <span class="identifier">ctx_</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">0</span><span class="special">>(</span><span class="identifier">result</span><span class="special">));</span> | |
334 | <span class="keyword">void</span> <span class="special">*</span> <span class="identifier">ret</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">get</span><span class="special"><</span><span class="number">1</span><span class="special">>(</span><span class="identifier">result</span><span class="special">);</span> | |
335 | <span class="keyword">if</span><span class="special">(</span><span class="identifier">excptr_</span><span class="special">){</span> | |
336 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">rethrow_exception</span><span class="special">(</span><span class="identifier">excptr_</span><span class="special">);</span> | |
337 | <span class="special">}</span> | |
338 | <span class="keyword">return</span> <span class="special">*</span> <span class="keyword">static_cast</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">*>(</span><span class="identifier">ret</span><span class="special">);</span> | |
339 | <span class="special">}</span> | |
340 | <span class="special">};</span> | |
341 | ||
342 | <span class="identifier">X</span> <span class="identifier">x</span><span class="special">;</span> | |
343 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">x</span><span class="special">(</span> <span class="number">7</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
344 | ||
345 | <span class="identifier">output</span><span class="special">:</span> | |
346 | <span class="number">7</span> | |
347 | </pre> | |
348 | <h4> | |
349 | <a name="context.ecv2_class.h5"></a> | |
350 | <span><a name="context.ecv2_class.class__code__phrase_role__identifier__execution_context__phrase___code_"></a></span><a class="link" href="ecv2_class.html#context.ecv2_class.class__code__phrase_role__identifier__execution_context__phrase___code_">Class | |
351 | <code class="computeroutput"><span class="identifier">execution_context</span></code></a> | |
352 | </h4> | |
353 | <pre class="programlisting"><span class="keyword">class</span> <span class="identifier">execution_context</span> <span class="special">{</span> | |
354 | <span class="keyword">public</span><span class="special">:</span> | |
355 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
356 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
357 | ||
358 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">StackAlloc</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
359 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator_arg_t</span><span class="special">,</span> <span class="identifier">StackAlloc</span> <span class="identifier">salloc</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
360 | ||
361 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">StackAlloc</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
362 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator_arg_t</span><span class="special">,</span> <span class="identifier">preallocated</span> <span class="identifier">palloc</span><span class="special">,</span> <span class="identifier">StackAlloc</span> <span class="identifier">salloc</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
363 | ||
364 | ||
365 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
366 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator_arg_t</span><span class="special">,</span> <span class="identifier">segemented_stack</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">)</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span> | |
367 | ||
368 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
369 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator_arg_t</span><span class="special">,</span> <span class="identifier">preallocated</span> <span class="identifier">palloc</span><span class="special">,</span> <span class="identifier">segmented</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">)=</span> <span class="keyword">delete</span><span class="special">;</span> | |
370 | <span class="special">~</span><span class="identifier">execution_context</span><span class="special">();</span> | |
371 | ||
372 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">execution_context</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
373 | <span class="identifier">execution_context</span> <span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span> <span class="identifier">execution_context</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
374 | ||
375 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">noexcept</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span> | |
376 | <span class="identifier">execution_context</span> <span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">noexcept</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span> | |
377 | ||
378 | <span class="keyword">explicit</span> <span class="keyword">operator</span> <span class="keyword">bool</span><span class="special">()</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
379 | <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
380 | ||
381 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">tuple</span><span class="special"><</span> <span class="identifier">execution_context</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">*</span> <span class="special">></span> <span class="keyword">operator</span><span class="special">()(</span> <span class="keyword">void</span> <span class="special">*</span> <span class="identifier">data</span> <span class="special">=</span> <span class="keyword">nullptr</span><span class="special">);</span> | |
382 | ||
383 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
384 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">tuple</span><span class="special"><</span> <span class="identifier">execution_context</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">*</span> <span class="special">></span> <span class="keyword">operator</span><span class="special">()(</span> <span class="identifier">exec_ontop_arg_t</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
385 | ||
386 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
387 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">tuple</span><span class="special"><</span> <span class="identifier">execution_context</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">*</span> <span class="special">></span> <span class="keyword">operator</span><span class="special">()(</span> <span class="keyword">void</span> <span class="special">*</span> <span class="identifier">data</span><span class="special">,</span> <span class="identifier">exec_ontop_arg_t</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
388 | ||
389 | <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">==(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
390 | ||
391 | <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!=(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
392 | ||
393 | <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special"><(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
394 | ||
395 | <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">>(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
396 | ||
397 | <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special"><=(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
398 | ||
399 | <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">>=(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
400 | ||
401 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">charT</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">traitsT</span> <span class="special">></span> | |
402 | <span class="keyword">friend</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">charT</span><span class="special">,</span> <span class="identifier">traitsT</span> <span class="special">></span> <span class="special">&</span> | |
403 | <span class="keyword">operator</span><span class="special"><<(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">charT</span><span class="special">,</span> <span class="identifier">traitsT</span> <span class="special">></span> <span class="special">&</span> <span class="identifier">os</span><span class="special">,</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span> | |
404 | <span class="special">};</span> | |
405 | </pre> | |
406 | <p> | |
407 | </p> | |
408 | <h5> | |
409 | <a name="ecv2_constructor_bridgehead"></a> | |
410 | <span><a name="ecv2_constructor"></a></span> | |
411 | <a class="link" href="ecv2_class.html#ecv2_constructor">Constructor</a> | |
412 | </h5> | |
413 | <p> | |
414 | </p> | |
415 | <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
416 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
417 | ||
418 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">StackAlloc</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
419 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator_arg_t</span><span class="special">,</span> <span class="identifier">StackAlloc</span> <span class="identifier">salloc</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
420 | ||
421 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">StackAlloc</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
422 | <span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator_arg_t</span><span class="special">,</span> <span class="identifier">preallocated</span> <span class="identifier">palloc</span><span class="special">,</span> <span class="identifier">StackAlloc</span> <span class="identifier">salloc</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
423 | </pre> | |
424 | <div class="variablelist"> | |
425 | <p class="title"><b></b></p> | |
426 | <dl> | |
427 | <dt><span class="term">Effects:</span></dt> | |
428 | <dd><p> | |
429 | Creates a new execution context and prepares the context to execute | |
430 | <code class="computeroutput"><span class="identifier">fn</span></code>. <code class="computeroutput"><span class="identifier">fixedsize_stack</span></code> | |
431 | is used as default stack allocator (stack size == fixedsize_stack::traits::default_size()). | |
432 | The constructor with argument type <code class="computeroutput"><span class="identifier">preallocated</span></code>, | |
433 | is used to create a user defined data <a class="link" href="../">(for | |
434 | instance additional control structures)</a> on top of the stack. | |
435 | </p></dd> | |
436 | </dl> | |
437 | </div> | |
438 | <p> | |
439 | </p> | |
440 | <h5> | |
441 | <a name="ecv2_move%20constructor_bridgehead"></a> | |
442 | <span><a name="ecv2_move%20constructor"></a></span> | |
443 | <a class="link" href="ecv2_class.html#ecv2_move%20constructor">Move | |
444 | constructor</a> | |
445 | </h5> | |
446 | <p> | |
447 | </p> | |
448 | <pre class="programlisting"><span class="identifier">execution_context</span><span class="special">(</span> <span class="identifier">execution_context</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
449 | </pre> | |
450 | <div class="variablelist"> | |
451 | <p class="title"><b></b></p> | |
452 | <dl> | |
453 | <dt><span class="term">Effects:</span></dt> | |
454 | <dd><p> | |
455 | Moves underlying capture record to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>. | |
456 | </p></dd> | |
457 | <dt><span class="term">Throws:</span></dt> | |
458 | <dd><p> | |
459 | Nothing. | |
460 | </p></dd> | |
461 | </dl> | |
462 | </div> | |
463 | <p> | |
464 | </p> | |
465 | <h5> | |
466 | <a name="ecv2_move%20assignment_bridgehead"></a> | |
467 | <span><a name="ecv2_move%20assignment"></a></span> | |
468 | <a class="link" href="ecv2_class.html#ecv2_move%20assignment">Move | |
469 | assignment operator</a> | |
470 | </h5> | |
471 | <p> | |
472 | </p> | |
473 | <pre class="programlisting"><span class="identifier">execution_context</span> <span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span> <span class="identifier">execution_context</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
474 | </pre> | |
475 | <div class="variablelist"> | |
476 | <p class="title"><b></b></p> | |
477 | <dl> | |
478 | <dt><span class="term">Effects:</span></dt> | |
479 | <dd><p> | |
480 | Moves the state of <code class="computeroutput"><span class="identifier">other</span></code> | |
481 | to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> | |
482 | using move semantics. | |
483 | </p></dd> | |
484 | <dt><span class="term">Throws:</span></dt> | |
485 | <dd><p> | |
486 | Nothing. | |
487 | </p></dd> | |
488 | </dl> | |
489 | </div> | |
490 | <p> | |
491 | </p> | |
492 | <h5> | |
493 | <a name="ecv2_operator_bool_bridgehead"></a> | |
494 | <span><a name="ecv2_operator_bool"></a></span> | |
495 | <a class="link" href="ecv2_class.html#ecv2_operator_bool">Member function | |
496 | <code class="computeroutput">operator bool</code>()</a> | |
497 | </h5> | |
498 | <p> | |
499 | </p> | |
500 | <pre class="programlisting"><span class="keyword">explicit</span> <span class="keyword">operator</span> <span class="keyword">bool</span><span class="special">()</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
501 | </pre> | |
502 | <div class="variablelist"> | |
503 | <p class="title"><b></b></p> | |
504 | <dl> | |
505 | <dt><span class="term">Returns:</span></dt> | |
506 | <dd><p> | |
507 | <code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> points to a capture record. | |
508 | </p></dd> | |
509 | <dt><span class="term">Throws:</span></dt> | |
510 | <dd><p> | |
511 | Nothing. | |
512 | </p></dd> | |
513 | </dl> | |
514 | </div> | |
515 | <p> | |
516 | </p> | |
517 | <h5> | |
518 | <a name="ecv2_operator_not_bridgehead"></a> | |
519 | <span><a name="ecv2_operator_not"></a></span> | |
520 | <a class="link" href="ecv2_class.html#ecv2_operator_not">Member function | |
521 | <code class="computeroutput">operator!</code>()</a> | |
522 | </h5> | |
523 | <p> | |
524 | </p> | |
525 | <pre class="programlisting"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
526 | </pre> | |
527 | <div class="variablelist"> | |
528 | <p class="title"><b></b></p> | |
529 | <dl> | |
530 | <dt><span class="term">Returns:</span></dt> | |
531 | <dd><p> | |
532 | <code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> does not point to a capture record. | |
533 | </p></dd> | |
534 | <dt><span class="term">Throws:</span></dt> | |
535 | <dd><p> | |
536 | Nothing. | |
537 | </p></dd> | |
538 | </dl> | |
539 | </div> | |
540 | <p> | |
541 | </p> | |
542 | <h5> | |
543 | <a name="ecv2_operator_call_bridgehead"></a> | |
544 | <span><a name="ecv2_operator_call"></a></span> | |
545 | <a class="link" href="ecv2_class.html#ecv2_operator_call">Member function | |
546 | <code class="computeroutput">operator()</code>()</a> | |
547 | </h5> | |
548 | <p> | |
549 | </p> | |
550 | <pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">tuple</span><span class="special"><</span> <span class="identifier">execution_context</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">*</span> <span class="special">></span> <span class="keyword">operator</span><span class="special">()(</span> <span class="keyword">void</span> <span class="special">*</span> <span class="identifier">data</span> <span class="special">=</span> <span class="keyword">nullptr</span><span class="special">);</span> | |
551 | </pre> | |
552 | <div class="variablelist"> | |
553 | <p class="title"><b></b></p> | |
554 | <dl> | |
555 | <dt><span class="term">Effects:</span></dt> | |
556 | <dd><p> | |
557 | Stores internally the current context data (stack pointer, instruction | |
558 | pointer, and CPU registers) of the current active context and restores | |
559 | the context data from <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>, which implies jumping to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>'s | |
560 | context. The void pointer argument, <code class="computeroutput"><span class="identifier">vp</span></code>, | |
561 | is passed to the current context to be returned by the most recent call | |
562 | to <code class="computeroutput"><span class="identifier">execution_context</span><span class="special">::</span><span class="keyword">operator</span><span class="special">()</span></code> in the same thread. <code class="computeroutput"><span class="identifier">fn</span></code> | |
563 | is executed with arguments <code class="computeroutput"><span class="identifier">args</span></code> | |
564 | on top of the stack of <code class="computeroutput"><span class="keyword">this</span></code>. | |
565 | </p></dd> | |
566 | <dt><span class="term">Note:</span></dt> | |
567 | <dd><p> | |
568 | The behaviour is undefined if <code class="computeroutput"><span class="keyword">operator</span><span class="special">()()</span></code> is called while <code class="computeroutput"><span class="identifier">execution_context</span><span class="special">::</span><span class="identifier">current</span><span class="special">()</span></code> returns <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> (e.g. resuming an already running | |
569 | context). If the top-level context function returns, <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">exit</span><span class="special">()</span></code> is called. | |
570 | </p></dd> | |
571 | <dt><span class="term">Returns:</span></dt> | |
572 | <dd><p> | |
573 | The tuple of void pointer argument passed to the most recent call to | |
574 | <code class="computeroutput"><span class="identifier">execution_context</span><span class="special">::</span><span class="keyword">operator</span><span class="special">()</span></code>, | |
575 | if any and a execution_context representing the context that has been | |
576 | suspended . | |
577 | </p></dd> | |
578 | </dl> | |
579 | </div> | |
580 | <p> | |
581 | </p> | |
582 | <h5> | |
583 | <a name="ecv2_operator_call_ontop_bridgehead"></a> | |
584 | <span><a name="ecv2_operator_call_ontop"></a></span> | |
585 | <a class="link" href="ecv2_class.html#ecv2_operator_call_ontop">Member | |
586 | function <code class="computeroutput">operator()</code>()</a> | |
587 | </h5> | |
588 | <p> | |
589 | </p> | |
590 | <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
591 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">tuple</span><span class="special"><</span> <span class="identifier">execution_context</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">*</span> <span class="special">></span> <span class="keyword">operator</span><span class="special">()(</span> <span class="identifier">exec_ontop_arg_t</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
592 | ||
593 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> | |
594 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">tuple</span><span class="special"><</span> <span class="identifier">execution_context</span><span class="special">,</span> <span class="keyword">void</span> <span class="special">*</span> <span class="special">></span> <span class="keyword">operator</span><span class="special">()(</span> <span class="keyword">void</span> <span class="special">*</span> <span class="identifier">data</span><span class="special">,</span> <span class="identifier">exec_ontop_arg_t</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span><span class="special">);</span> | |
595 | </pre> | |
596 | <div class="variablelist"> | |
597 | <p class="title"><b></b></p> | |
598 | <dl> | |
599 | <dt><span class="term">Effects:</span></dt> | |
600 | <dd><p> | |
601 | Same as <span class="emphasis"><em>execution_context::operator()</em></span>. Additionally, | |
602 | function <code class="computeroutput"><span class="identifier">fn</span></code> is executed | |
603 | with arguments <code class="computeroutput"><span class="identifier">args</span></code> in | |
604 | the context of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> | |
605 | (e.g. the stack frame of <code class="computeroutput"><span class="identifier">fn</span></code> | |
606 | is allocated on stack of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>). | |
607 | </p></dd> | |
608 | <dt><span class="term">Returns:</span></dt> | |
609 | <dd><p> | |
610 | The tuple of void pointer argument passed to the most recent call to | |
611 | <code class="computeroutput"><span class="identifier">execution_context</span><span class="special">::</span><span class="keyword">operator</span><span class="special">()</span></code>, | |
612 | if any and a execution_context representing the context that has been | |
613 | suspended . | |
614 | </p></dd> | |
615 | </dl> | |
616 | </div> | |
617 | <p> | |
618 | </p> | |
619 | <h5> | |
620 | <a name="ecv2_operator_equal_bridgehead"></a> | |
621 | <span><a name="ecv2_operator_equal"></a></span> | |
622 | <a class="link" href="ecv2_class.html#ecv2_operator_equal">Member | |
623 | function <code class="computeroutput">operator==</code>()</a> | |
624 | </h5> | |
625 | <p> | |
626 | </p> | |
627 | <pre class="programlisting"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">==(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
628 | </pre> | |
629 | <div class="variablelist"> | |
630 | <p class="title"><b></b></p> | |
631 | <dl> | |
632 | <dt><span class="term">Returns:</span></dt> | |
633 | <dd><p> | |
634 | <code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> and <code class="computeroutput"><span class="identifier">other</span></code> | |
635 | represent the same execution context, <code class="computeroutput"><span class="keyword">false</span></code> | |
636 | otherwise. | |
637 | </p></dd> | |
638 | <dt><span class="term">Throws:</span></dt> | |
639 | <dd><p> | |
640 | Nothing. | |
641 | </p></dd> | |
642 | </dl> | |
643 | </div> | |
644 | <p> | |
645 | </p> | |
646 | <h5> | |
647 | <a name="ecv2_operator_notequal_bridgehead"></a> | |
648 | <span><a name="ecv2_operator_notequal"></a></span> | |
649 | <a class="link" href="ecv2_class.html#ecv2_operator_notequal">Member | |
650 | function <code class="computeroutput">operator!=</code>()</a> | |
651 | </h5> | |
652 | <p> | |
653 | </p> | |
654 | <pre class="programlisting"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!=(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
655 | </pre> | |
656 | <div class="variablelist"> | |
657 | <p class="title"><b></b></p> | |
658 | <dl> | |
659 | <dt><span class="term">Returns:</span></dt> | |
660 | <dd><p> | |
661 | <code class="computeroutput">! (other == * this)</code> | |
662 | </p></dd> | |
663 | <dt><span class="term">Throws:</span></dt> | |
664 | <dd><p> | |
665 | Nothing. | |
666 | </p></dd> | |
667 | </dl> | |
668 | </div> | |
669 | <p> | |
670 | </p> | |
671 | <h5> | |
672 | <a name="ecv2_operator_less_bridgehead"></a> | |
673 | <span><a name="ecv2_operator_less"></a></span> | |
674 | <a class="link" href="ecv2_class.html#ecv2_operator_less">Member function | |
675 | <code class="computeroutput">operator<</code>()</a> | |
676 | </h5> | |
677 | <p> | |
678 | </p> | |
679 | <pre class="programlisting"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special"><(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
680 | </pre> | |
681 | <div class="variablelist"> | |
682 | <p class="title"><b></b></p> | |
683 | <dl> | |
684 | <dt><span class="term">Returns:</span></dt> | |
685 | <dd><p> | |
686 | <code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span> <span class="special">!=</span> <span class="identifier">other</span></code> is true and the implementation-defined | |
687 | total order of <code class="computeroutput"><span class="identifier">execution_context</span></code> | |
688 | values places <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> | |
689 | before <code class="computeroutput"><span class="identifier">other</span></code>, false otherwise. | |
690 | </p></dd> | |
691 | <dt><span class="term">Throws:</span></dt> | |
692 | <dd><p> | |
693 | Nothing. | |
694 | </p></dd> | |
695 | </dl> | |
696 | </div> | |
697 | <p> | |
698 | </p> | |
699 | <h5> | |
700 | <a name="ecv2_operator_greater_bridgehead"></a> | |
701 | <span><a name="ecv2_operator_greater"></a></span> | |
702 | <a class="link" href="ecv2_class.html#ecv2_operator_greater">Member | |
703 | function <code class="computeroutput">operator></code>()</a> | |
704 | </h5> | |
705 | <p> | |
706 | </p> | |
707 | <pre class="programlisting"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">>(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
708 | </pre> | |
709 | <div class="variablelist"> | |
710 | <p class="title"><b></b></p> | |
711 | <dl> | |
712 | <dt><span class="term">Returns:</span></dt> | |
713 | <dd><p> | |
714 | <code class="computeroutput"><span class="identifier">other</span> <span class="special"><</span> | |
715 | <span class="special">*</span> <span class="keyword">this</span></code> | |
716 | </p></dd> | |
717 | <dt><span class="term">Throws:</span></dt> | |
718 | <dd><p> | |
719 | Nothing. | |
720 | </p></dd> | |
721 | </dl> | |
722 | </div> | |
723 | <p> | |
724 | </p> | |
725 | <h5> | |
726 | <a name="ecv2_operator_lesseq_bridgehead"></a> | |
727 | <span><a name="ecv2_operator_lesseq"></a></span> | |
728 | <a class="link" href="ecv2_class.html#ecv2_operator_lesseq">Member | |
729 | function <code class="computeroutput">operator<=</code>()</a> | |
730 | </h5> | |
731 | <p> | |
732 | </p> | |
733 | <pre class="programlisting"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special"><=(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
734 | </pre> | |
735 | <div class="variablelist"> | |
736 | <p class="title"><b></b></p> | |
737 | <dl> | |
738 | <dt><span class="term">Returns:</span></dt> | |
739 | <dd><p> | |
740 | <code class="computeroutput"><span class="special">!</span> <span class="special">(</span><span class="identifier">other</span> <span class="special"><</span> | |
741 | <span class="special">*</span> <span class="keyword">this</span><span class="special">)</span></code> | |
742 | </p></dd> | |
743 | <dt><span class="term">Throws:</span></dt> | |
744 | <dd><p> | |
745 | Nothing. | |
746 | </p></dd> | |
747 | </dl> | |
748 | </div> | |
749 | <p> | |
750 | </p> | |
751 | <h5> | |
752 | <a name="ecv2_operator_greatereq_bridgehead"></a> | |
753 | <span><a name="ecv2_operator_greatereq"></a></span> | |
754 | <a class="link" href="ecv2_class.html#ecv2_operator_greatereq">Member | |
755 | function <code class="computeroutput">operator>=</code>()</a> | |
756 | </h5> | |
757 | <p> | |
758 | </p> | |
759 | <pre class="programlisting"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">>=(</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span> | |
760 | </pre> | |
761 | <div class="variablelist"> | |
762 | <p class="title"><b></b></p> | |
763 | <dl> | |
764 | <dt><span class="term">Returns:</span></dt> | |
765 | <dd><p> | |
766 | <code class="computeroutput"><span class="special">!</span> <span class="special">(*</span> | |
767 | <span class="keyword">this</span> <span class="special"><</span> | |
768 | <span class="identifier">other</span><span class="special">)</span></code> | |
769 | </p></dd> | |
770 | <dt><span class="term">Throws:</span></dt> | |
771 | <dd><p> | |
772 | Nothing. | |
773 | </p></dd> | |
774 | </dl> | |
775 | </div> | |
776 | <p> | |
777 | </p> | |
778 | <h5> | |
779 | <a name="ecv2_bridgehead"></a> | |
780 | <span><a name="ecv2"></a></span> | |
781 | <a class="link" href="ecv2_class.html#ecv2">Non-member function <code class="computeroutput">operator<<()</code></a> | |
782 | </h5> | |
783 | <p> | |
784 | </p> | |
785 | <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">charT</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">traitsT</span> <span class="special">></span> | |
786 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">charT</span><span class="special">,</span> <span class="identifier">traitsT</span> <span class="special">></span> <span class="special">&</span> | |
787 | <span class="keyword">operator</span><span class="special"><<(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">charT</span><span class="special">,</span> <span class="identifier">traitsT</span> <span class="special">></span> <span class="special">&</span> <span class="identifier">os</span><span class="special">,</span> <span class="identifier">execution_context</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span> | |
788 | </pre> | |
789 | <div class="variablelist"> | |
790 | <p class="title"><b></b></p> | |
791 | <dl> | |
792 | <dt><span class="term">Efects:</span></dt> | |
793 | <dd><p> | |
794 | Writes the representation of <code class="computeroutput"><span class="identifier">other</span></code> | |
795 | to stream <code class="computeroutput"><span class="identifier">os</span></code>. | |
796 | </p></dd> | |
797 | <dt><span class="term">Returns:</span></dt> | |
798 | <dd><p> | |
799 | <code class="computeroutput"><span class="identifier">os</span></code> | |
800 | </p></dd> | |
801 | </dl> | |
802 | </div> | |
803 | </div> | |
804 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
805 | <td align="left"></td> | |
806 | <td align="right"><div class="copyright-footer">Copyright © 2014 Oliver Kowalke<p> | |
807 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
808 | file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) | |
809 | </p> | |
810 | </div></td> | |
811 | </tr></table> | |
812 | <hr> | |
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