----- Original Message -----

From: Ashutosh Warikoo

To: threads-devel@lists.boost.org

Sent: Tuesday, September 14, 2010 11:21 AM

Subject: [Threads-devel] Request Help On boost::lock_error

Hello
I am trying to model a usecase where a member function reads in a value & now has to modify the value by calling another function. The code which I have written using upgrade_locks fails at run time. I have gone through the documentation & have cleared the code as best as I could to arrive at a condensed usecase. I have also attached some sample erroneous outputs & a backtrace of the thread in question. Can someone please have a look? 
 
[...]

int boostThreadLocksTest::firstFunction(boostThreadLocksTest *pBoostThreadLocksTest)
{ 
        pBoostThreadLocksTest->myLock.lock(); 
        pBoostThreadLocksTest->secondFunction(pBoostThreadLocksTest); 
        pBoostThreadLocksTest->myLock.unlock(); 
        return(0);
}
int boostThreadLocksTest::secondFunction(boostThreadLocksTest *pBoostThreadLocksTest)
{ 
        boost::upgrade_to_unique_lock<boost::shared_mutex> localUniqueLock(pBoostThreadLocksTest->myLock); 
        return(0);
}
***********************************************

 

Hi,

 

Unfortunately boost::shared_mutex is not recursive :(.

 

Why do you use a shared mutex if you lock it exclusively in firstFunction and secondFunction? upgrade_to_unique_lock has a sens only if the mutext has been lock_shared. Shouldn't you user lock_shared()/unlock_shared() in firstFunction?

 

Best,

Vicente