Re: Mutex scoped_lock compile errors

From: Russell Hind (yg-boost-users_at_[hidden])
Date: 2003-06-10 09:41:25

Darren Vincent Hart wrote:
> That did the trick, many thanks.  So why is it that the error talked
> about argument types when it *should* have reported me attempting to
> change a member variable within a const context ? (I admit to feeling a
> bit abashed at the problem however :-) )
> 

The compiler is correct with its error (whether it is a helpful 
diagnostic or not).  You are passing a const mutex to an method that 
expects a mutex.  Its like passing an int to method that expects a string.

const mutex

is a different type than

mutex.

So that is why the error is about argument types.  You weren't actually 
attempting to modify a const object yourself was, but scoped_lock 
explicitly states that it wants a 'mutex', not a 'const mutex' so that 
is the error the compiler was displaying

C++ compiler errors aren't always the most helpful, but they are logical 
(usually)

Russell