Re: [Boost-users] Locking mechanisms other than scoped_lock

From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-03-21 14:10:19

Howard Hinnant wrote:

> On Mar 19, 2005, at 1:29 PM, Leon Mergen wrote:

[...]

>> Now, since it is very well possible a thread handles at least 1,000
>> jobs before statistics data is actually read from, I want it to hold a
>> mutex lock to the data at all time. [...]
>
> This sounds like a good application for condition variables:
>
> http://www.boost.org/doc/html/condition.html

Yes. Mutexes should never be used to block a thread until some event occurs. 
Their purpose is to serialize access to a shared resource, and you should 
strive to make the section between the lock and the unlock as short as 
possible. The design of scoped_lock tries to point you in that direction.

Condition variables are the proper primitive to make a thread wait for an 
event.