stdio performance in tango, stdlib, and perl

[Sean Kelly]

torhu wrote:
> James Dennett wrote:
> <snip>
>> Try the way IOStreams would be used if you didn't want
>> it to go slowly:
>>
>> #include <string>
>> #include <iostream>
>>
>> int main() {
>>     std::ios_base::sync_with_stdio(false);
>>     std::cin.tie(NULL);
>>     std::string s;
>>     while (std::getline(std::cin, s)) {
>>         std::cout << s << '\n';
>>     }
>> }
> <snip>
> 
> 
> I did some tests with a 58 MB file, containing one million lines.  I'm 
> on winxp.  I ran each test a few times, timing them with a stopwatch.  I 
> threw in a naive C version, and a std.cstream version, just out of 
> curiousity.
> 
> It seems that using cin.tie(NULL) doesn't matter with msvc 7.1, but with 
> mingw it does.  Basically, Tango wins hands down on my system.  Whether 
> the Tango version flushes after each line or not, doesn't seem to matter 
> much on Windows.
...
> ---
> // Tango
> import tango.io.Console;
> 
> void main() {
>   char[] line;
> 
>   while (Cin.nextLine(line)) {
>     //Cout(line).newline;
>     Cout(line)("\n");
>   }
> }
> ---

Oh good.  I was hoping someone would test Tango without flushing every 
line :-)  Basically, Tango's 'newline' method is equivalent to C++'s 
'endl' mutator function.  It should not be used for every carriage 
return in normal output for performance-critical applications.  Rather, 
it should be used as the trailing newline after writing a block of data 
that should be displayed immediately ('flush' is another option if no 
newline is desired).


Sean