source: sema.c hush-3.0b4/auxiliary/net/thread

  // a simple semaphore class
  //
  // October 1995
  // Bastiaan Sch\"onhage
  
  include <hush/source.h>
  
  include <net/thread/thread.h>
  include <net/thread/semaphore.h>
  include <hush/flags.h>
  
  ifdef THREADS
  include <synch.h>
  endif
  
  ifndef THREADS
  semaphore::semaphore(int, int ) {
  else
  semaphore::semaphore(int count, int process) {
          sp = new sema_t;
          if (process) sema_init((sema_t*) sp, count, USYNC_PROCESS, 0);
          else sema_init((sema_t*) sp, count, USYNC_THREAD, 0);
  endif
  }
  
  semaphore::~semaphore()
  {
  ifdef THREADS
          sema_destroy((sema_t*)sp);
          delete (sema_t*)sp;
  endif
  }
  
  void semaphore::up()
  {
  ifdef THREADS
          sema_post((sema_t*) sp);
  endif
  }
  
  void semaphore::down()
  {        
  ifdef THREADS
          sema_wait((sema_t*) sp);
  endif
  }
  
  int semaphore::trydown()
  {
  ifdef THREADS
          if( sema_trywait((sema_t*) sp) == 0) return 1;
          else return 0;
  else
          return 0;
  endif
  }
  

Hush Online Technology hush@cs.vu.nl 09/09/98