overloading operators for I/O

[Andrei Alexandrescu (See Website For Email)]

Walter Bright wrote:
> Michiel wrote:
>> Bill Baxter wrote:
>>
>>>> But it has the added advantage that there is no need for run-time
>>>> parsing of that string. C++ parses all << stuff at compile time.
>>>>
>>> I wonder how much difference that makes given that most IO tends to be
>>> slow anyway.   On a 1 GHz proc, with a disk that has 10msec seek time
>>> that means a hit to the disk can cost you ten million cycles, right?
>>>
>>> Spending a few cycles to parse a format string at runtime isn't going to
>>> kill you.
>>
>> Well, you're right of course. But strictly speaking it's still an
>> advantage. ;)
> 
> C++ iostreams has the further "advantage" of being neither 
> exception-safe nor thread-safe (since it manipulates global state in 
> order to do formatting). This is only excusable because iostreams was 
> added to C++ years before exception handling was and before anyone knew 
> anything about threaded programming.

It's a myth that iostreams benefit much the speed advantage of not 
needing to do type retrieval at runtime. They are marred by a convoluted 
design and the need to synchronize with C's stdio library. By the time 
you saved that penny, you've spent all of those pounds already.

Andrei