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Changes from Version 1 of ThreadsAndDelegatesExample

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Author:
jcc7 (IP: 192.149.244.9)
Timestamp:
05/22/07 20:35:31 (14 years ago)
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added example

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  • ThreadsAndDelegatesExample

    v0 v1  
     1= Threads and Delegates = 
     2 
     3''Part of'' [StandardLibraryCategory Standard Library Category] 
     4 
     5== Example == 
     6 
     7{{{ 
     8#!d 
     9import std.c.time; 
     10import std.stdio; 
     11import std.thread; 
     12 
     13class Foo 
     14{ 
     15   int _v; 
     16 
     17   this(int n) 
     18   { 
     19      _v = n; 
     20   } 
     21 
     22   public int glob() 
     23   { 
     24      return _v; 
     25   } 
     26} 
     27 
     28class WorkerThread 
     29{ 
     30   int _v; 
     31 
     32   this(int n) 
     33   { 
     34      _v = n; 
     35   } 
     36 
     37   // Here's a private member function - we'll call this from the run() method 
     38   void identify() 
     39   { 
     40      writefln("WorkerThread(%d)", _v); 
     41   } 
     42 
     43   // When run is called via the delegate it will have the appropriate this 
     44   // pointer, and so has access to all the fields and methods of its class. 
     45   public int run() 
     46   { 
     47      for (;;) 
     48      { 
     49         sleep(2); 
     50         identify(); 
     51      } 
     52      return 0; 
     53   } 
     54} 
     55 
     56// In the thread 2 case, we override the thread class, and provide the run method 
     57// explicitly 
     58class Thread2 : Thread 
     59{ 
     60   int _v; 
     61 
     62   this(int n) 
     63   { 
     64      _v = n; 
     65   } 
     66   public int run() 
     67   { 
     68      for (;;) 
     69      { 
     70         sleep(2); 
     71         writefln("Thread2 %d", _v);; 
     72      } 
     73      return 0; 
     74   } 
     75} 
     76 
     77void bar(int delegate() a) 
     78{ 
     79   writefln("rv = %d", a()); 
     80} 
     81 
     82// In the case of thread 3, this will serve as the run method, and 
     83// it will be called with the value of the second argument to the 
     84// thread constructor (the documentation is not correct in this respect). 
     85int x(void *p) 
     86{ 
     87   int *ip = cast(int*) p; 
     88   for (;;) 
     89   { 
     90      sleep(2); 
     91      writefln("Thread3 %d", *ip); 
     92   } 
     93   return 0; 
     94} 
     95 
     96 
     97void main(char[][] args) 
     98{ 
     99   // Before we get to threads, these first few lines just illustrate the 
     100   // general ideas of delegates as applied to class member functions. 
     101   Foo foo = new Foo(42); 
     102   int delegate() dg = &foo.glob; 
     103   int n = dg(); 
     104   writefln("n = %d", n); 
     105   bar(dg); 
     106   int n3 = 123; 
     107 
     108   // Now the different ways of instantiating threads. 
     109   WorkerThread wt = new WorkerThread(22); 
     110   dg = &wt.run; 
     111   Thread t1 = new Thread(dg); 
     112   t1.start(); 
     113 
     114   Thread2 t2 = new Thread2(321); 
     115   t2.start(); 
     116 
     117   Thread t3 = new Thread(&x, &n3); 
     118   t3.start(); 
     119 
     120   sleep(10); 
     121}  
     122}}} 
     123 
     124== Sample Batch File == 
     125 
     126{{{ 
     127@echo off 
     128set pgm=ThreadsAndDelegatesExample 
     129dmd %pgm%.d  
     130%pgm%.exe 
     131 
     132pause 
     133erase *.obj 
     134erase *.map 
     135}}} 
     136 
     137 
     138== Tested Environment == 
     139 
     140Tested with Digital Mars D Compiler v1.014 on Windows 2000. 
     141 
     142 
     143== Source == 
     144 
     145Based on "[http://www.dsource.org/forums/viewtopic.php?t=2752 Threads, delegates, and all that]" by teales.