RE: Are PR_Locks thread re-entrant?

I use Monitors to allow reentrant lock. It works for my very well.

I have implemented two classes: Monitor and Lockable.

Follows the code: (Monitor.h, Monitor.cpp, Lockable.h, Lockable.cpp)

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------------------------------------------------------------------

#include <nspr.h>
#include <prmon.h>

#ifndef _MONITOR_H
#define _MONITOR_H

class Monitor
{
 private:
   PRMonitor*monitor; 
 public:
   Monitor();
   virtual ~Monitor();
   
   void enter();
   void exit();
   bool wait(PRIntervalTime ticks);
   void notify(bool all=false);
};

#endif

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------------------------------------------------------------------

#include "Monitor.h"

Monitor::Monitor() 
{ 
 monitor=PR_NewMonitor(); 
}
 
Monitor::~Monitor() 
{ 
 PR_DestroyMonitor(monitor);
}
  
void Monitor::enter()
{
 PR_EnterMonitor(monitor);
}

void Monitor::exit()
{
 PR_ExitMonitor(monitor);
}

bool Monitor::wait(PRIntervalTime ticks)
{
 return (PR_Wait(monitor,ticks)==PR_SUCCESS);
}

void Monitor::notify(bool all)
{
 if(all)
   {
    PR_NotifyAll(monitor);
   }
 else
   {
    PR_Notify(monitor);
   }
}

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------------------------------------------------------------------

#include "Monitor.h"

#ifndef _LOCKABLE_H
#define _LOCKABLE_H

class Lockable: protected Monitor
{
 private:
 public:
   Lockable();
   virtual ~Lockable();
  
   void lock();
   void unlock();
};

#endif

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------------------------------------------------------------------

#include "Lockable.h"

Lockable::Lockable(): Monitor()
{ 
}
 
Lockable::~Lockable() 
{ 
}
  
void Lockable::lock()   
{
 enter();
}

void Lockable::unlock() 
{ 
 exit();
}

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------------------------------------------------------------------

As you can see I use PR_EnterMonitor and PR_ExitMonitor to implement Lock
and Unlock.

Monitor operations are reentrant.

-----Mensaje original-----
De: [email protected]
[mailto:[email protected]] En nombre
de Rich Megginson
Enviado el: sábado, 20 de septiembre de 2008 1:25
Para: [email protected]
Asunto: Re: Are PR_Locks thread re-entrant?

Wan-Teh Chang wrote:
> On Fri, Sep 19, 2008 at 4:08 PM, Rich Megginson
> <[email protected]> wrote:
>> That is, can you lock a mutex more than once in the same thread?  We
>> have a case where a function acquires a PR_Lock mutex and is called
>> recursively.
> 
> No, you can't lock a PRLock more than once in the same thread.
> That's a programming error.

Any suggestions?  I need to allow re-entrant code in the same thread but 
lock out other threads.

> 
> Wan-Teh
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