stdio line-streaming revisited

[Frits van Bommel]

Andrei Alexandrescu (See Website For Email) wrote:
> Frits van Bommel wrote:
>> Andrei Alexandrescu (See Website For Email) wrote:
>>> Sean Kelly wrote:
>>>> Andrei Alexandrescu (See Website For Email) wrote:
>>>>> That's great, however the interface has a problem too: it does not 
>>>>> produce atomic strings in multithreaded programs.
>>>>
>>>> Which interface?  And are you talking about input or output?
>>>
>>> Cout. The thing is that the design using the syntax Cout(a)(b) is 
>>> conducive to two separate calls to the library. I recall this has 
>>> been briefly discussed here.
>>
>> Of course that could easily be fixed if either struct destructors or 
>> scope class returning were to be added to the language. Then you could 
>> just return something with a destructor that releases the lock.
> 
> Struct destructors will be added, but typesafe variadics are already in. 
> I think Cout(a, b) is the most natural interface to offer.

I dislike typesafe variadics for I/O, mainly because it'll instantiate a 
new version for every parameter list. I/O functions will typically be 
called with a lot of different parameter lists, which may lead to code 
bloat.

However, my point in that post was that using the method I suggested 
(the first call returning a struct with a destructor) also has the 
advantage that it allows for backwards-compatibility. The current syntax 
will continue to work, with the only difference being that now it'll be 
thread-safe.