Re: [boost] Re: A simple monitor for Boost

From: Kevlin Henney (kevlin_at_[hidden])
Date: 2000-08-10 11:49:52

In message <8mui65+jteo_at_[hidden]>, William Kempf <sirwillard_at_my-
deja.com> writes
>I've taken a look at the classic 1974 paper by Hoare, and this paper 
>has a very good example of why the simplistic monitor you've 
>described can not be a replacement for conditions.  He's got an 
>example of a read/write lock implemented using his concept of a 
>monitor.  The implementation requires two conditions.  I'm not sure 
>that a monitor deserves first class implementation in a C++ library 
>given this.  The monitor as Hoare describes it may simply be a 
>programming idiom used with mutexes and conditions.  That's 
>definately something that's up to debate, but I think I've proven to 
>myself that we can't do with out the primitives mutex and condition 
>just because we include a monitor.

Yes, I am not sure why we are having a discussion on monitors vs
mutexes. Mutexes (and conditions) provide us with a primitive layer on
which we can build the higher-level programming models. If you like,
monitors are applied mutexes/conditions.

So without synchronisation primitives in our library we can't build
monitors, but with only monitors we can't easily build concurrent apps
:->

We should provide the primitives that allow monitors and other
approaches to be built, as well as providing some of these higher-level
concepts directly in the library.
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