Subj : Re: Recursive mutexes
To   : comp.programming.threads
From : Chris Thomasson
Date : Thu Mar 24 2005 03:51 pm

> Not in my system. Why you assume I'm using windows? :-)

DOH!

I instantly thought windows because you used EnterCriticalSection. I failed 
to see the call to ExitCriticalSection. Windows has 
EnterCriticalSection/LeaveCriticalSection API's. Thats what confuused me.




>(In fact, AFAIK, windows does support recursive mutexes).

Yes it does.


> No, in my case they're implemented with a semaphore, so calling it twice 
> in a row
> in the same thread would deadlock. This is an embedded system, and the 
> synchronization support
> isn't very good. It's quite minimal. This is why I need to do it by 
> myself.

Ok, you can do it like this:


void my_mutex::acquire() {
if (m_owner == thread_id) {
    ++m_count;
    return;
}

EnterCriticalSection();
m_owner = thread_id;
}




void my_mutex::release() {
if (m_count) {
    --m_count;
    if ( m_count ) { return; }
}

m_owner = 0;
ExitCriticalSection();
}

.