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| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h2 class="title" style="clear: both"> |
| <a name="context.econtext"></a><a class="link" href="econtext.html" title="Class execution_context">Class execution_context</a> |
| </h2></div></div></div> |
| <div class="important"><table border="0" summary="Important"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../doc/src/images/important.png"></td> |
| <th align="left">Important</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| <span class="emphasis"><em>execution_context</em></span> is supported only by C++14. |
| </p></td></tr> |
| </table></div> |
| <p> |
| Class <span class="emphasis"><em>execution_context</em></span> encapsulates <span class="emphasis"><em>fcontext_t</em></span> |
| and related functions ( <span class="emphasis"><em>jump_fcontext()</em></span> and <span class="emphasis"><em>make_fcontext()</em></span>) |
| as well as stack management. <span class="emphasis"><em>execution_context</em></span> permits |
| access to the current, active context via <code class="computeroutput"><span class="identifier">execution_context</span><span class="special">::</span><span class="identifier">current</span><span class="special">()</span></code>. |
| </p> |
| <pre class="programlisting"><span class="comment">/* |
| * grammar: |
| * P ---> E '\0' |
| * E ---> T {('+'|'-') T} |
| * T ---> S {('*'|'/') S} |
| * S ---> digit | '(' E ')' |
| */</span> |
| <span class="keyword">class</span> <span class="identifier">Parser</span><span class="special">{</span> |
| <span class="comment">// implementation omitted; see examples directory</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> <span class="special">{</span> |
| <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> |
| <span class="keyword">bool</span> <span class="identifier">done</span><span class="special">=</span><span class="keyword">false</span><span class="special">;</span> |
| <span class="keyword">char</span> <span class="identifier">c</span><span class="special">;</span> |
| |
| <span class="comment">// create handle to main execution context</span> |
| <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">main_ctx</span><span class="special">(</span> |
| <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="special">::</span><span class="identifier">current</span><span class="special">()</span> <span class="special">);</span> |
| |
| <span class="comment">// executes parser in new execution context</span> |
| <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">parser_ctx</span><span class="special">(</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">context</span><span class="special">::</span><span class="identifier">fixedsize_stack</span><span class="special">(),</span> |
| <span class="special">[&</span><span class="identifier">main_ctx</span><span class="special">,&</span><span class="identifier">is</span><span class="special">,&</span><span class="identifier">c</span><span class="special">,&</span><span class="identifier">done</span><span class="special">](){</span> |
| <span class="comment">// create parser with callback function</span> |
| <span class="identifier">Parser</span> <span class="identifier">p</span><span class="special">(</span><span class="identifier">is</span><span class="special">,</span> |
| <span class="special">[&</span><span class="identifier">main_ctx</span><span class="special">,&</span><span class="identifier">c</span><span class="special">](</span><span class="keyword">char</span> <span class="identifier">ch</span><span class="special">){</span> |
| <span class="identifier">c</span><span class="special">=</span><span class="identifier">ch</span><span class="special">;</span> |
| <span class="comment">// resume main execution context</span> |
| <span class="identifier">main_ctx</span><span class="special">.</span><span class="identifier">resume</span><span class="special">();</span> |
| <span class="special">});</span> |
| <span class="comment">// start recursive parsing</span> |
| <span class="identifier">p</span><span class="special">.</span><span class="identifier">run</span><span class="special">();</span> |
| <span class="identifier">done</span><span class="special">=</span><span class="keyword">true</span><span class="special">;</span> |
| <span class="comment">// return to main execution context</span> |
| <span class="identifier">main_ctx</span><span class="special">.</span><span class="identifier">resume</span><span class="special">();</span> |
| <span class="special">});</span> |
| |
| <span class="comment">// user-code pulls parsed data from parser</span> |
| <span class="comment">// inverted control flow</span> |
| <span class="identifier">parser_ctx</span><span class="special">.</span><span class="identifier">resume</span><span class="special">();</span> |
| <span class="keyword">do</span> <span class="special">{</span> |
| <span class="identifier">printf</span><span class="special">(</span><span class="string">"Parsed: %c\n"</span><span class="special">,</span><span class="identifier">c</span><span class="special">);</span> |
| <span class="identifier">parser_ctx</span><span class="special">.</span><span class="identifier">resume</span><span class="special">();</span> |
| <span class="special">}</span> <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> |
| |
| <span class="identifier">output</span><span class="special">:</span> |
| <span class="identifier">Parsed</span><span class="special">:</span> <span class="number">1</span> |
| <span class="identifier">Parsed</span><span class="special">:</span> <span class="special">+</span> |
| <span class="identifier">Parsed</span><span class="special">:</span> <span class="number">1</span> |
| </pre> |
| <p> |
| In this example a recursive descent parser uses a callback to emit a newly |
| passed symbol. Using <span class="emphasis"><em>execution_context</em></span> the control flow |
| can be inverted, e.g. the user-code pulls parsed symbols from the parser - |
| instead to get pushed from the parser (via callback). |
| </p> |
| <p> |
| The interface of <span class="emphasis"><em>execution_context</em></span> does not transfer data. |
| This is not required because usually sharing data's address (pointer/reference) |
| sufficient. |
| </p> |
| <p> |
| If the code executed by <span class="emphasis"><em>execution_context</em></span> emits an exception, |
| <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">terminate</span><span class="special">()</span></code> |
| will be called. |
| </p> |
| <div class="important"><table border="0" summary="Important"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../doc/src/images/important.png"></td> |
| <th align="left">Important</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| Do not jump from inside a catch block and than re-throw exceptions in another |
| execution context. |
| </p></td></tr> |
| </table></div> |
| <p> |
| Sometimes it is necessary to unwind the stack of an unfinished context to destroy |
| local stack variables so they can release allocated resources (RAII pattern). |
| The user is responsible for this task. |
| </p> |
| <h4> |
| <a name="context.econtext.h0"></a> |
| <span class="phrase"><a name="context.econtext.allocating_control_strutures_on_top_of_stack"></a></span><a class="link" href="econtext.html#context.econtext.allocating_control_strutures_on_top_of_stack">allocating |
| control strutures on top of stack</a> |
| </h4> |
| <p> |
| Allocating control structures on top of the stack requires to allocated the |
| <span class="emphasis"><em>stack_context</em></span> and create the control structure with placement |
| new before <span class="emphasis"><em>execution_context</em></span> is created. |
| </p> |
| <div class="note"><table border="0" summary="Note"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td> |
| <th align="left">Note</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| The user is responsible for destructing the control structure at the top |
| of the stack. |
| </p></td></tr> |
| </table></div> |
| <pre class="programlisting"><span class="comment">// stack-alloctor used for (de-)allocating stack</span> |
| <span class="identifier">fixedsize_stack</span> <span class="identifier">salloc</span><span class="special">(</span> <span class="number">4048</span><span class="special">);</span> |
| <span class="comment">// allocate stack space</span> |
| <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> |
| <span class="comment">// reserve space for control structure on top of the stack</span> |
| <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> |
| <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> |
| <span class="comment">// placement new creates control structure on reserved space</span> |
| <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> |
| <span class="special">...</span> |
| <span class="comment">// destructing the control structure</span> |
| <span class="identifier">cs</span><span class="special">->~</span><span class="identifier">my_control_structure</span><span class="special">();</span> |
| <span class="special">...</span> |
| <span class="keyword">struct</span> <span class="identifier">my_control_structure</span> <span class="special">{</span> |
| <span class="comment">// execution context</span> |
| <span class="identifier">execution_context</span> <span class="identifier">ectx</span><span class="special">;</span> |
| |
| <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">StackAllocator</span> <span class="special">></span> |
| <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> |
| <span class="comment">// create execution context</span> |
| <span class="identifier">ectx</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> |
| <span class="special">}</span> |
| <span class="special">...</span> |
| <span class="special">};</span> |
| </pre> |
| <h4> |
| <a name="context.econtext.h1"></a> |
| <span class="phrase"><a name="context.econtext.exception_handling"></a></span><a class="link" href="econtext.html#context.econtext.exception_handling">exception |
| handling</a> |
| </h4> |
| <p> |
| If the function executed inside a <span class="emphasis"><em>execution_context</em></span> emitts |
| ans exception, <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">terminate</span><span class="special">()</span></code> |
| is called - <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">exception_ptr</span></code> can used to store exceptions |
| thrown inside the other context. |
| </p> |
| <h4> |
| <a name="context.econtext.h2"></a> |
| <span class="phrase"><a name="context.econtext.parameter_passing"></a></span><a class="link" href="econtext.html#context.econtext.parameter_passing">parameter |
| passing</a> |
| </h4> |
| <p> |
| Input and output parameters are transfered via a lambda capture list and references/pointers. |
| </p> |
| <pre class="programlisting"><span class="keyword">class</span> <span class="identifier">X</span> <span class="special">{</span> |
| <span class="keyword">private</span><span class="special">:</span> |
| <span class="keyword">int</span> <span class="special">*</span> <span class="identifier">inp_</span><span class="special">;</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">outp_</span><span class="special">;</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">exception_ptr</span> <span class="identifier">excptr_</span><span class="special">;</span> |
| <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">caller_</span><span class="special">;</span> |
| <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">callee_</span><span class="special">;</span> |
| |
| <span class="keyword">public</span><span class="special">:</span> |
| <span class="identifier">X</span><span class="special">()</span> <span class="special">:</span> |
| <span class="identifier">inp_</span><span class="special">(</span> <span class="keyword">nullptr</span><span class="special">),</span> |
| <span class="identifier">outp_</span><span class="special">(),</span> |
| <span class="identifier">excptr_</span><span class="special">(),</span> |
| <span class="identifier">caller_</span><span class="special">(</span> <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="special">::</span><span class="identifier">current</span><span class="special">()</span> <span class="special">),</span> |
| <span class="identifier">callee_</span><span class="special">(</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">context</span><span class="special">::</span><span class="identifier">fixedsize_stack</span><span class="special">(),</span> |
| <span class="special">[=]</span> <span class="special">()</span> <span class="special">{</span> |
| <span class="keyword">try</span> <span class="special">{</span> |
| <span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="special">*</span> <span class="identifier">inp_</span><span class="special">;</span> |
| <span class="identifier">outp_</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> |
| <span class="identifier">caller_</span><span class="special">.</span><span class="identifier">resume</span><span class="special">();</span> |
| <span class="special">}</span> <span class="keyword">catch</span> <span class="special">(...)</span> <span class="special">{</span> |
| <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> |
| <span class="special">}</span> |
| <span class="special">})</span> |
| <span class="special">{}</span> |
| |
| <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> |
| <span class="identifier">inp_</span> <span class="special">=</span> <span class="special">&</span> <span class="identifier">i</span><span class="special">;</span> |
| <span class="identifier">callee_</span><span class="special">.</span><span class="identifier">resume</span><span class="special">();</span> |
| <span class="keyword">if</span> <span class="special">(</span> <span class="identifier">excptr_</span><span class="special">)</span> <span class="special">{</span> |
| <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> |
| <span class="special">}</span> |
| <span class="keyword">return</span> <span class="identifier">outp_</span><span class="special">;</span> |
| <span class="special">}</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> <span class="special">{</span> |
| <span class="identifier">X</span> <span class="identifier">x</span><span class="special">;</span> |
| <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> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"done"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> |
| <span class="special">}</span> |
| </pre> |
| <h4> |
| <a name="context.econtext.h3"></a> |
| <span class="phrase"><a name="context.econtext.class__code__phrase_role__identifier__execution_context__phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext.class__code__phrase_role__identifier__execution_context__phrase___code_">Class |
| <code class="computeroutput"><span class="identifier">execution_context</span></code></a> |
| </h4> |
| <pre class="programlisting"><span class="keyword">class</span> <span class="identifier">execution_context</span> <span class="special">{</span> |
| <span class="keyword">public</span><span class="special">:</span> |
| <span class="keyword">static</span> <span class="identifier">execution_context</span> <span class="identifier">current</span><span class="special">()</span> <span class="keyword">noexcept</span><span class="special">;</span> |
| |
| <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="identifier">execution_context</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="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> |
| <span class="identifier">execution_context</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> |
| |
| <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="identifier">execution_context</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="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> |
| <span class="identifier">execution_context</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> |
| |
| <span class="keyword">void</span> <span class="identifier">resume</span><span class="special">()</span> <span class="keyword">noexcept</span><span class="special">;</span> |
| |
| <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> |
| |
| <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> |
| <span class="special">};</span> |
| </pre> |
| <h4> |
| <a name="context.econtext.h4"></a> |
| <span class="phrase"><a name="context.econtext._code__phrase_role__keyword__static__phrase___phrase_role__identifier__execution_context__phrase___phrase_role__identifier__current__phrase__phrase_role__special______phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext._code__phrase_role__keyword__static__phrase___phrase_role__identifier__execution_context__phrase___phrase_role__identifier__current__phrase__phrase_role__special______phrase___code_"><code class="computeroutput"><span class="keyword">static</span> <span class="identifier">execution_context</span> |
| <span class="identifier">current</span><span class="special">()</span></code></a> |
| </h4> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl class="variablelist"> |
| <dt><span class="term">Returns:</span></dt> |
| <dd><p> |
| Returns an instance of excution_context pointing to the active execution |
| context. |
| </p></dd> |
| <dt><span class="term">Throws:</span></dt> |
| <dd><p> |
| Nothing. |
| </p></dd> |
| </dl> |
| </div> |
| <h4> |
| <a name="context.econtext.h5"></a> |
| <span class="phrase"><a name="context.econtext._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__stackalloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__typname__phrase___phrase_role__identifier__fn__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__execution_context__phrase__phrase_role__special_____phrase___phrase_role__identifier__stackalloc__phrase___phrase_role__identifier__salloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__stackalloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__typname__phrase___phrase_role__identifier__fn__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__execution_context__phrase__phrase_role__special_____phrase___phrase_role__identifier__stackalloc__phrase___phrase_role__identifier__salloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___code_"><code class="computeroutput"><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="identifier">typname</span> <span class="identifier">Fn</span> <span class="special">></span> <span class="identifier">execution_context</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></code></a> |
| </h4> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl class="variablelist"> |
| <dt><span class="term">Effects:</span></dt> |
| <dd><p> |
| Creates a new execution context and prepares the context to execute |
| <code class="computeroutput"><span class="identifier">fn</span></code>. |
| </p></dd> |
| </dl> |
| </div> |
| <h4> |
| <a name="context.econtext.h6"></a> |
| <span class="phrase"><a name="context.econtext._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__stackalloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__typname__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__special_______phrase___phrase_role__identifier__args__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__execution_context__phrase__phrase_role__special_____phrase___phrase_role__identifier__stackalloc__phrase___phrase_role__identifier__salloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__args__phrase___phrase_role__special___amp__amp___phrase___phrase_role__special_______phrase___phrase_role__identifier__args__phrase__phrase_role__special_____phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__stackalloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__typname__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__special_______phrase___phrase_role__identifier__args__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__execution_context__phrase__phrase_role__special_____phrase___phrase_role__identifier__stackalloc__phrase___phrase_role__identifier__salloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__args__phrase___phrase_role__special___amp__amp___phrase___phrase_role__special_______phrase___phrase_role__identifier__args__phrase__phrase_role__special_____phrase___code_"><code class="computeroutput"><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="identifier">typname</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> <span class="identifier">execution_context</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></code></a> |
| </h4> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl class="variablelist"> |
| <dt><span class="term">Effects:</span></dt> |
| <dd><p> |
| Creates a new execution context and prepares the context to execute |
| <code class="computeroutput"><span class="identifier">fn</span></code>. |
| </p></dd> |
| </dl> |
| </div> |
| <h4> |
| <a name="context.econtext.h7"></a> |
| <span class="phrase"><a name="context.econtext._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__stackalloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__typname__phrase___phrase_role__identifier__fn__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__execution_context__phrase__phrase_role__special_____phrase___phrase_role__identifier__preallocated__phrase___phrase_role__identifier__palloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__stackalloc__phrase___phrase_role__identifier__salloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__stackalloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__typname__phrase___phrase_role__identifier__fn__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__execution_context__phrase__phrase_role__special_____phrase___phrase_role__identifier__preallocated__phrase___phrase_role__identifier__palloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__stackalloc__phrase___phrase_role__identifier__salloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___code_"><code class="computeroutput"><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="identifier">typname</span> <span class="identifier">Fn</span> <span class="special">></span> <span class="identifier">execution_context</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></code></a> |
| </h4> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl class="variablelist"> |
| <dt><span class="term">Effects:</span></dt> |
| <dd><p> |
| Creates a new execution context and prepares the context to execute |
| <code class="computeroutput"><span class="identifier">fn</span></code>. Used to store control |
| structures on top of the stack. |
| </p></dd> |
| </dl> |
| </div> |
| <h4> |
| <a name="context.econtext.h8"></a> |
| <span class="phrase"><a name="context.econtext._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__stackalloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__typname__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__special_______phrase___phrase_role__identifier__args__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__execution_context__phrase__phrase_role__special_____phrase___phrase_role__identifier__preallocated__phrase___phrase_role__identifier__palloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__stackalloc__phrase___phrase_role__identifier__salloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__args__phrase___phrase_role__special___amp__amp___phrase___phrase_role__special_______phrase___phrase_role__identifier__args__phrase__phrase_role__special_____phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__stackalloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__typname__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__special_______phrase___phrase_role__identifier__args__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__execution_context__phrase__phrase_role__special_____phrase___phrase_role__identifier__preallocated__phrase___phrase_role__identifier__palloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__stackalloc__phrase___phrase_role__identifier__salloc__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__args__phrase___phrase_role__special___amp__amp___phrase___phrase_role__special_______phrase___phrase_role__identifier__args__phrase__phrase_role__special_____phrase___code_"><code class="computeroutput"><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="identifier">typname</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> <span class="identifier">execution_context</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></code></a> |
| </h4> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl class="variablelist"> |
| <dt><span class="term">Effects:</span></dt> |
| <dd><p> |
| Creates a new execution context and prepares the context to execute |
| <code class="computeroutput"><span class="identifier">fn</span></code>. Used to store control |
| structures on top of the stack. |
| </p></dd> |
| </dl> |
| </div> |
| <h4> |
| <a name="context.econtext.h9"></a> |
| <span class="phrase"><a name="context.econtext._code__phrase_role__keyword__void__phrase___phrase_role__identifier__resume__phrase__phrase_role__special______phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext._code__phrase_role__keyword__void__phrase___phrase_role__identifier__resume__phrase__phrase_role__special______phrase___code_"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">resume</span><span class="special">()</span></code></a> |
| </h4> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl class="variablelist"> |
| <dt><span class="term">Effects:</span></dt> |
| <dd><p> |
| Stores internally the current context data (stack pointer, instruction |
| pointer, and CPU registers) to the current active context and restores |
| 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 |
| execution context. |
| </p></dd> |
| <dt><span class="term">Note:</span></dt> |
| <dd><p> |
| The behaviour is undefined if <code class="computeroutput"><span class="identifier">resume</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 alredy running |
| cotnext). |
| </p></dd> |
| <dt><span class="term">Throws:</span></dt> |
| <dd><p> |
| Nothing. |
| </p></dd> |
| </dl> |
| </div> |
| <h4> |
| <a name="context.econtext.h10"></a> |
| <span class="phrase"><a name="context.econtext._code__phrase_role__keyword__explicit__phrase___phrase_role__keyword__operator__phrase___phrase_role__keyword__bool__phrase__phrase_role__special______phrase___phrase_role__keyword__const__phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext._code__phrase_role__keyword__explicit__phrase___phrase_role__keyword__operator__phrase___phrase_role__keyword__bool__phrase__phrase_role__special______phrase___phrase_role__keyword__const__phrase___code_"><code class="computeroutput"><span class="keyword">explicit</span> <span class="keyword">operator</span> |
| <span class="keyword">bool</span><span class="special">()</span> <span class="keyword">const</span></code></a> |
| </h4> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl class="variablelist"> |
| <dt><span class="term">Returns:</span></dt> |
| <dd><p> |
| If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> |
| refers to an invalid context or the context-function has returned (completed), |
| the function returns <code class="computeroutput"><span class="keyword">false</span></code>. |
| Otherwise <code class="computeroutput"><span class="keyword">true</span></code>. |
| </p></dd> |
| <dt><span class="term">Throws:</span></dt> |
| <dd><p> |
| Nothing. |
| </p></dd> |
| </dl> |
| </div> |
| <h4> |
| <a name="context.econtext.h11"></a> |
| <span class="phrase"><a name="context.econtext._code__phrase_role__keyword__bool__phrase___phrase_role__keyword__operator__phrase__phrase_role__special_______phrase___phrase_role__keyword__const__phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext._code__phrase_role__keyword__bool__phrase___phrase_role__keyword__operator__phrase__phrase_role__special_______phrase___phrase_role__keyword__const__phrase___code_"><code class="computeroutput"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span></code></a> |
| </h4> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl class="variablelist"> |
| <dt><span class="term">Returns:</span></dt> |
| <dd><p> |
| If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> |
| refers to an invalid context or the context-function has returned (completed), |
| the function returns <code class="computeroutput"><span class="keyword">true</span></code>. |
| Otherwise <code class="computeroutput"><span class="keyword">false</span></code>. |
| </p></dd> |
| <dt><span class="term">Throws:</span></dt> |
| <dd><p> |
| Nothing. |
| </p></dd> |
| </dl> |
| </div> |
| <h4> |
| <a name="context.econtext.h12"></a> |
| <span class="phrase"><a name="context.econtext.struct__code__phrase_role__identifier__preallocated__phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext.struct__code__phrase_role__identifier__preallocated__phrase___code_">Struct |
| <code class="computeroutput"><span class="identifier">preallocated</span></code></a> |
| </h4> |
| <pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">preallocated</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">preallocated</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_allocator</span> <span class="identifier">sctx</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span> |
| <span class="special">};</span> |
| </pre> |
| <h4> |
| <a name="context.econtext.h13"></a> |
| <span class="phrase"><a name="context.econtext._code__phrase_role__identifier__preallocated__phrase__phrase_role__special_____phrase___phrase_role__keyword__void__phrase___phrase_role__special_____phrase___phrase_role__identifier__sp__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special_____phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__stack_allocator__phrase___phrase_role__identifier__sctx__phrase__phrase_role__special_____phrase___code_"></a></span><a class="link" href="econtext.html#context.econtext._code__phrase_role__identifier__preallocated__phrase__phrase_role__special_____phrase___phrase_role__keyword__void__phrase___phrase_role__special_____phrase___phrase_role__identifier__sp__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special_____phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__stack_allocator__phrase___phrase_role__identifier__sctx__phrase__phrase_role__special_____phrase___code_"><code class="computeroutput"><span class="identifier">preallocated</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_allocator</span> |
| <span class="identifier">sctx</span><span class="special">)</span></code></a> |
| </h4> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl class="variablelist"> |
| <dt><span class="term">Effects:</span></dt> |
| <dd><p> |
| Crreates an object of preallocated. |
| </p></dd> |
| </dl> |
| </div> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2014 Oliver Kowalke<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| 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>) |
| </p> |
| </div></td> |
| </tr></table> |
| <hr> |
| <div class="spirit-nav"> |
| <a accesskey="p" href="context.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="stack.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> |
| </div> |
| </body> |
| </html> |
