a00019.html

Protothreads are extremely lightweight stackless threads designed for severely memory constrained s

00165 <span class="comment">   PT_WAIT_UNTIL(p, time &gt;= 2 * SECOND);</span>
00166 <span class="comment">   printf("Two seconds have passed\n");</span>
00167 <span class="comment">   </span>
00168 <span class="comment">   PT_END(p);</span>
00169 <span class="comment"> }</span>
00170 <span class="comment"> \endcode</span>
00171 <span class="comment"> *</span>
00172 <span class="comment"> * \hideinitializer</span>
00173 <span class="comment"> */</span>
<a name="l00174"></a><a class="code" href="a00012.html#ga5">00174</a> <span class="preprocessor">#define PT_WAIT_UNTIL(pt, condition)            \</span>
00175 <span class="preprocessor">  do {                                          \</span>
00176 <span class="preprocessor">    LC_SET((pt)-&gt;lc);                           \</span>
00177 <span class="preprocessor">    if(!(condition)) {                          \</span>
00178 <span class="preprocessor">      return PT_THREAD_WAITING;                 \</span>
00179 <span class="preprocessor">    }                                           \</span>
00180 <span class="preprocessor">  } while(0)</span>
00181 <span class="preprocessor"></span><span class="comment"></span>
00182 <span class="comment">/**</span>
00183 <span class="comment"> * Block and wait while condition is true.</span>
00184 <span class="comment"> *</span>
00185 <span class="comment"> * This function blocks and waits while condition is true. See</span>
00186 <span class="comment"> * PT_WAIT_UNTIL().</span>
00187 <span class="comment"> *</span>
00188 <span class="comment"> * \param pt A pointer to the protothread control structure.</span>
00189 <span class="comment"> * \param cond The condition.</span>
00190 <span class="comment"> *</span>
00191 <span class="comment"> * \hideinitializer</span>
00192 <span class="comment"> */</span>
<a name="l00193"></a><a class="code" href="a00012.html#ga6">00193</a> <span class="preprocessor">#define PT_WAIT_WHILE(pt, cond)                 \</span>
00194 <span class="preprocessor">  PT_WAIT_UNTIL((pt), !(cond))</span>
00195 <span class="preprocessor"></span>
00196 <span class="comment"></span>
00197 <span class="comment">/**</span>
00198 <span class="comment"> * Block and wait until a child protothread completes.</span>
00199 <span class="comment"> *</span>
00200 <span class="comment"> * This macro schedules a child protothread. The current protothread</span>
00201 <span class="comment"> * will block until the child protothread completes.</span>
00202 <span class="comment"> *</span>
00203 <span class="comment"> * \note The child protothread must be manually initialized with the</span>
00204 <span class="comment"> * PT_INIT() function before this function is used.</span>
00205 <span class="comment"> *</span>
00206 <span class="comment"> * \param pt A pointer to the protothread control structure.</span>
00207 <span class="comment"> * \param thread The child protothread with arguments</span>
00208 <span class="comment"> *</span>
00209 <span class="comment"> * Example:</span>
00210 <span class="comment"> \code</span>
00211 <span class="comment"> PT_THREAD(child(struct pt *p, int event)) {</span>
00212 <span class="comment">   PT_BEGIN(p);</span>
00213 <span class="comment"></span>
00214 <span class="comment">   PT_WAIT_UNTIL(event == EVENT1);   </span>
00215 <span class="comment">   </span>
00216 <span class="comment">   PT_END(p);</span>
00217 <span class="comment"> }</span>
00218 <span class="comment"></span>
00219 <span class="comment"> PT_THREAD(parent(struct pt *p, struct pt *child_pt, int event)) {</span>
00220 <span class="comment">   PT_BEGIN(p);</span>
00221 <span class="comment"></span>
00222 <span class="comment">   PT_INIT(child_pt);</span>
00223 <span class="comment">   </span>
00224 <span class="comment">   PT_WAIT_THREAD(p, child(child_pt, event));</span>
00225 <span class="comment">   </span>
00226 <span class="comment">   PT_END(p);</span>
00227 <span class="comment"> }</span>
00228 <span class="comment"> \endcode</span>
00229 <span class="comment"> *</span>
00230 <span class="comment"> * \hideinitializer </span>
00231 <span class="comment"> */</span>
<a name="l00232"></a><a class="code" href="a00012.html#ga7">00232</a> <span class="preprocessor">#define PT_WAIT_THREAD(pt, thread)              \</span>
00233 <span class="preprocessor">  PT_WAIT_UNTIL((pt), (thread))</span>
00234 <span class="preprocessor"></span><span class="comment"></span>
00235 <span class="comment">/**</span>
00236 <span class="comment"> * Spawn a child protothread and wait until it exits.</span>
00237 <span class="comment"> *</span>
00238 <span class="comment"> * This macro spawns a child protothread and waits until it exits. The</span>
00239 <span class="comment"> * macro can only be used within a protothread.</span>
00240 <span class="comment"> *</span>
00241 <span class="comment"> * \param pt A pointer to the protothread control structure.</span>
00242 <span class="comment"> * \param thread The child protothread with arguments</span>
00243 <span class="comment"> *</span>
00244 <span class="comment"> * \hideinitializer</span>
00245 <span class="comment"> */</span>
<a name="l00246"></a><a class="code" href="a00012.html#ga8">00246</a> <span class="preprocessor">#define PT_SPAWN(pt, thread)                    \</span>
00247 <span class="preprocessor">  do {                                          \</span>
00248 <span class="preprocessor">    PT_INIT((pt));                              \</span>
00249 <span class="preprocessor">    PT_WAIT_THREAD((pt), (thread));             \</span>
00250 <span class="preprocessor">  } while(0)</span>
00251 <span class="preprocessor"></span><span class="comment"></span>
00252 <span class="comment">/**</span>
00253 <span class="comment"> * Restart the protothread.</span>
00254 <span class="comment"> *</span>
00255 <span class="comment"> * This macro will block and cause the running protothread to restart</span>
00256 <span class="comment"> * its execution at the place of the PT_BEGIN() call.</span>
00257 <span class="comment"> *</span>
00258 <span class="comment"> * \param pt A pointer to the protothread control structure.</span>
00259 <span class="comment"> *</span>
00260 <span class="comment"> * \hideinitializer</span>
00261 <span class="comment"> */</span>
<a name="l00262"></a><a class="code" href="a00012.html#ga9">00262</a> <span class="preprocessor">#define PT_RESTART(pt)                          \</span>
00263 <span class="preprocessor">  do {                                          \</span>
00264 <span class="preprocessor">    PT_INIT(pt);                                \</span>
00265 <span class="preprocessor">    return PT_THREAD_WAITING;                   \</span>
00266 <span class="preprocessor">  } while(0)</span>
00267 <span class="preprocessor"></span><span class="comment"></span>
00268 <span class="comment">/**</span>
00269 <span class="comment"> * Exit the protothread.</span>
00270 <span class="comment"> *</span>
00271 <span class="comment"> * This macro causes the protothread to exit. If the protothread was</span>
00272 <span class="comment"> * spawned by another protothread, the parent protothread will become</span>
00273 <span class="comment"> * unblocked and can continue to run.</span>
00274 <span class="comment"> *</span>
00275 <span class="comment"> * \param pt A pointer to the protothread control structure.</span>
00276 <span class="comment"> *</span>
00277 <span class="comment"> * \hideinitializer</span>
00278 <span class="comment"> */</span>
<a name="l00279"></a><a class="code" href="a00012.html#ga10">00279</a> <span class="preprocessor">#define PT_EXIT(pt)                             \</span>
00280 <span class="preprocessor">  do {                                          \</span>
00281 <span class="preprocessor">    PT_INIT(pt);                                \</span>
00282 <span class="preprocessor">    return PT_THREAD_EXITED;                    \</span>
00283 <span class="preprocessor">  } while(0)</span>
00284 <span class="preprocessor"></span><span class="comment"></span>
00285 <span class="comment">/**</span>
00286 <span class="comment"> * Declare the end of a protothread.</span>
00287 <span class="comment"> *</span>
00288 <span class="comment"> * This macro is used for declaring that a protothread ends. It should</span>
00289 <span class="comment"> * always be used together with a matching PT_BEGIN() macro.</span>
00290 <span class="comment"> *</span>
00291 <span class="comment"> * \param pt A pointer to the protothread control structure.</span>
00292 <span class="comment"> *</span>
00293 <span class="comment"> * \hideinitializer</span>
00294 <span class="comment"> */</span>
<a name="l00295"></a><a class="code" href="a00012.html#ga11">00295</a> <span class="preprocessor">#define PT_END(pt) LC_END((pt)-&gt;lc); PT_EXIT(pt)</span>
00296 <span class="preprocessor"></span>
00297 <span class="comment"></span>
00298 <span class="comment">/**</span>
00299 <span class="comment"> * Schedule a protothread.</span>
00300 <span class="comment"> *</span>
00301 <span class="comment"> * This function shedules a protothread. The return value of the</span>
00302 <span class="comment"> * function is non-zero if the protothread is running or zero if the</span>
00303 <span class="comment"> * protothread has exited.</span>
00304 <span class="comment"> *</span>
00305 <span class="comment"> * Example</span>
00306 <span class="comment"> \code</span>
00307 <span class="comment"> void main(void) {</span>
00308 <span class="comment">   struct pt p;</span>
00309 <span class="comment">   int event;</span>
00310 <span class="comment">   </span>
00311 <span class="comment">   PT_INIT(&amp;p);</span>
00312 <span class="comment">   while(PT_SCHEDULE(consumer(&amp;p, event))) {</span>
00313 <span class="comment">     event = get_event();</span>
00314 <span class="comment">   }   </span>
00315 <span class="comment"> }</span>
00316 <span class="comment"> \endcode</span>
00317 <span class="comment"> *</span>
00318 <span class="comment"> * \param f The call to the C function implementing the protothread to</span>
00319 <span class="comment"> * be scheduled</span>
00320 <span class="comment"> *</span>
00321 <span class="comment"> * \hideinitializer</span>
00322 <span class="comment"> */</span>
<a name="l00323"></a><a class="code" href="a00012.html#ga12">00323</a> <span class="preprocessor">#define PT_SCHEDULE(f) (f == PT_THREAD_WAITING)</span>
00324 <span class="preprocessor"></span>
00325 <span class="preprocessor">#endif </span><span class="comment">/* __PT_H__ */</span>
00326 
00327 <span class="comment"></span>
00328 <span class="comment">/** @} */</span>
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