Subj : Re: mutex problem
To   : comp.programming.threads
From : Torsten Robitzki
Date : Fri Jun 17 2005 10:20 am

LinuxGuy wrote:
> Hi,
> 
> I have one thread which locks the mutex in one function for certain
> purose. but while executing that portion I am calling another function
> from same thread and want to update some data but, data I want to
> update may create problem as earlier function may be using that.
>                in short how to use same mutex for  locking twice in
> same thread. means  I want to update same data structure in another
> function while other function using it  by loking mutex
> 
> any suggestion is welcome

Just don't lock the mutex in that second function. For the case that the 
second function requires that the mutex is locked, write a wrapper for 
the second function that just locks the mutex and then call that function.

void f1()
{
   mutex.lock();
   /* what ever */
   f2_impl();
}

void f2()
{
   mutex.lock();
   f2_impl();
}

void f2_impl()
{
   /* what ever */
}

This pattern is quit easy. Just split every function that needs a lock 
and can be called with or without holding the lock.

regards Torsten

.