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