Re: code pattern for locking & unlocking
On 28 nov, 15:31, Daniel Anderson <woni...@gmail.com> wrote:
On Nov 27, 1:40 am, Matt Calabrese <rivo...@gmail.com> wrote:
On Nov 25, 5:48 pm, Daniel Anderson <woni...@gmail.com> wrote:
I would like to have something like the using keyword in c#.
Is there a way to fake it in C++ ?
for now I'm using an if to do it.
The whole point of C# "using" is to specify a scope for an object and
its disposal. It's a way to emulate the behavior that C++ already
supports naturally -- by simply writing object declarations in C++ you
get the behavior of C# using. I'm not sure why you are treating it as
though it's a special feature of C#.
Is it good programming ?
Is there a better way ?
Your "if" example is not "bad" programming, just sort of silly and
unnecessary (and likely more confusing to someone reading your code).
The "better" way IMO is to just use braces as in your original
example. What do you think is so bad about plain braces?
I've worked with plenty of people at different places.
where I work now, we have plenty of "not talented" programmer (maybe
I'm one of them) . In the past it happen that some of my stand alone
braces where removed by some programmers that did not understand the
idioms.
Now I cannot put comments to say why I've put braces, as my boss
forbid them.
For him putting comments means that the code is not clear and he does
not want code that is not clear.
You can always name your lock variables:
{ Lock
Don_t_delete_this_brace_It_defines_the_lifetime_of_the_lock_of(mutex);
...
}
I suggest you put that as a snippet :)
Also he reasoned that if there is no comments, people will have to
understand the code before modifying it.
Time to be creative:)
assert( sedition && "this is not a comment" );
So I'm trying to find a way that people will not remove my braces.
Ok. So the solution may be to have a resetable lock:
struct Lock: non_copiable()
{
Lock(Mutex& mtx) mtx_(&mtx) { mtx.lock(); }
~Lock() { unlock(); }
void unlock() { if(mtx_) {mtx_->unlock();mtx_=0;} }
private:
Mutex* _mtx;
};
And use:
Lock lock(mutex)
....
lock.unlock();
You will have RAII unlock in case of early return and you have unlock
whenever you want.
The people after you will have to look for when the lock is released
but if it is what your boss does want.
--
Michael
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