test/threads.cxx

   1 //
   2 // "$Id: threads.cxx 8033 2010-12-15 12:11:16Z AlbrechtS $"
   3 //
   4 // Threading example program for the Fast Light Tool Kit (FLTK).
   5 //
   6 // Copyright 1998-2010 by Bill Spitzak and others.
   7 //
   8 // This library is free software; you can redistribute it and/or
   9 // modify it under the terms of the GNU Library General Public
  10 // License as published by the Free Software Foundation; either
  11 // version 2 of the License, or (at your option) any later version.
  12 //
  13 // This library is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 // Library General Public License for more details.
  17 //
  18 // You should have received a copy of the GNU Library General Public
  19 // License along with this library; if not, write to the Free Software
  20 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21 // USA.
  22 //
  23 // Please report all bugs and problems on the following page:
  24 //
  25 //     http://www.fltk.org/str.php
  26 //
  27
  28 #include <config.h>
  29
  30 #if HAVE_PTHREAD || defined(WIN32)
  31 #  include <FL/Fl.H>
  32 #  include <FL/Fl_Double_Window.H>
  33 #  include <FL/Fl_Browser.H>
  34 #  include <FL/Fl_Value_Output.H>
  35 #  include <FL/fl_ask.H>
  36 #  include "threads.h"
  37 #  include <stdio.h>
  38 #  include <math.h>
  39
  40 Fl_Thread prime_thread;
  41
  42 Fl_Browser *browser1, *browser2;
  43 Fl_Value_Output *value1, *value2;
  44 int start2 = 3;
  45
  46 void magic_number_cb(void *p)
  47 {
  48   Fl_Value_Output *w = (Fl_Value_Output*)p;
  49   w->labelcolor(FL_RED);
  50   w->redraw_label();
  51 }
  52
  53 void* prime_func(void* p)
  54 {
  55   Fl_Browser* browser = (Fl_Browser*) p;
  56   Fl_Value_Output *value;
  57   int n;
  58   int step;
  59   char proud = 0;
  60
  61   if (browser == browser2) {
  62     n      = start2;
  63     start2 += 2;
  64     step   = 12;
  65     value  = value2;
  66   } else {
  67     n     = 3;
  68     step  = 2;
  69     value = value1;
  70   }
  71
  72   // very simple prime number calculator !
  73   //
  74   // The return at the end of this function can never be reached and thus
  75   // will generate a warning with some compilers, however we need to have
  76   // a return statement or other compilers will complain there is no return
  77   // statement. To avoid warnings on all compilers, we fool the smart ones
  78   // into beleiving that there is a chance that we reach the end by testing
  79   // n>=0, knowing that logically, n will never be negative in this context.
  80   if (n>=0) for (;;) {
  81     int pp;
  82     int hn = (int)sqrt((double)n);
  83
  84     for (pp=3; pp<=hn; pp+=2) if ( n%pp == 0 ) break;
  85     if (pp >= hn) {
  86       char s[128];
  87       sprintf(s, "%d", n);
  88
  89       // Obtain a lock before we access the browser widget...
  90       Fl::lock();
  91
  92       browser->add(s);
  93       browser->bottomline(browser->size());
  94       if (n > value->value()) value->value(n);
  95       n += step;
  96
  97       // Release the lock...
  98       Fl::unlock();
  99
 100       // Send a message to the main thread, at which point it will
 101       // process any pending redraws for our browser widget.  The
 102       // message we pass here isn't used for anything, so we could also
 103       // just pass NULL.
 104       Fl::awake(p);
 105       if (n>10000 && !proud) {
 106         proud = 1;
 107         Fl::awake(magic_number_cb, value);
 108       }
 109     } else {
 110       // This should not be necessary since "n" and "step" are local variables,
 111       // however it appears that at least MacOS X has some threading issues
 112       // that cause semi-random corruption of the (stack) variables.
 113       Fl::lock();
 114       n += step;
 115       Fl::unlock();
 116     }
 117   }
 118   return 0L;
 119 }
 120
 121 int main(int argc, char **argv)
 122 {
 123   Fl_Double_Window* w = new Fl_Double_Window(200, 200, "Single Thread");
 124   browser1 = new Fl_Browser(0, 0, 200, 175);
 125   w->resizable(browser1);
 126   value1 = new Fl_Value_Output(100, 175, 200, 25, "Max Prime:");
 127   w->end();
 128   w->show(argc, argv);
 129   w = new Fl_Double_Window(200, 200, "Six Threads");
 130   browser2 = new Fl_Browser(0, 0, 200, 175);
 131   w->resizable(browser2);
 132   value2 = new Fl_Value_Output(100, 175, 200, 25, "Max Prime:");
 133   w->end();
 134   w->show();
 135
 136   browser1->add("Prime numbers:");
 137   browser2->add("Prime numbers:");
 138
 139   // Enable multi-thread support by locking from the main
 140   // thread.  Fl::wait() and Fl::run() call Fl::unlock() and
 141   // Fl::lock() as needed to release control to the child threads
 142   // when it is safe to do so...
 143   Fl::lock();
 144
 145   // Start threads...
 146
 147   // One thread displaying in one browser
 148   fl_create_thread(prime_thread, prime_func, browser1);
 149
 150   // Several threads displaying in another browser
 151   fl_create_thread(prime_thread, prime_func, browser2);
 152   fl_create_thread(prime_thread, prime_func, browser2);
 153   fl_create_thread(prime_thread, prime_func, browser2);
 154   fl_create_thread(prime_thread, prime_func, browser2);
 155   fl_create_thread(prime_thread, prime_func, browser2);
 156   fl_create_thread(prime_thread, prime_func, browser2);
 157
 158   Fl::run();
 159
 160   return 0;
 161 }
 162 #else
 163 #  include <FL/fl_ask.H>
 164
 165 int main() {
 166   fl_alert("Sorry, threading not supported on this platform!");
 167 }
 168 #endif // HAVE_PTHREAD || WIN32
 169
 170
 171 //
 172 // End of "$Id: threads.cxx 8033 2010-12-15 12:11:16Z AlbrechtS $".
 173 //