Subj : Re: Recursive mutexes
To   : comp.programming.threads
From : doug
Date : Sun Mar 27 2005 07:46 pm

"Marcin 'Qrczak' Kowalczyk" <qrczak@knm.org.pl> wrote in message 
news:87psxl6yfc.fsf@qrnik.zagroda...
> "doug" <noone@nowhere.co.uk> writes:
>
>> void my_mutex::acquire() {
>> EnterCriticalSection();
>> if (m_owner == thread_id) {
>>     ++m_count;
>> }
>> else {
>>     do
>> *  {
>> *    ExitCriticalSection();
>>       m_mutex->wait();
>> *    EnterCriticalSection();
>> *  } while (m_count > 0);
>>     m_count = 1;
>>     m_owner = thread_id;
>>  }
>> ExitCriticalSection();
>> }
>
> It should be while (m_count > 0) {...}, not do {...} while (m_count > 0).
>
> Alternatively m_count should be tested at the beginning, so the common
> case of the mutex being free is faster.

Indeed it should!
This is what you get for making it up on the fly on a Sunday morning after a 
heavy night out.

>
> -- 
>   __("<         Marcin Kowalczyk
>   \__/       qrczak@knm.org.pl
>    ^^     http://qrnik.knm.org.pl/~qrczak/

.