Re: Buffering in libstc++ 3.0

[Loren James Rittle <rittle at latour dot rsch dot comm dot mot dot com>]

In article <200108291722.f7THMMq15425@peti.cryp.to> you write:

> I have experienced some weird effects with g++ 3.0 and hope that you
> guys can explain to me what I am doing wrong. I compiled the program
>
> | #include <iostream>
> | using namespace std;
> | 
> | int main(int argc, char** argv)
> |     {
> | #ifdef NO_STDIO_SYNC
> |     ios::sync_with_stdio(false);
> | #endif
> | #ifdef USE_MY_BUFFER
> |     char buf[1*1024];
> |     cin.rdbuf()->pubsetbuf(buf, sizeof(buf));
> | #endif
> | 
> |     string line;
> |     for (getline(cin, line); cin; getline(cin, line))
> |      ;
> | 
> |     return 0;
> |     }

Hi Peter,

For systems that allow fseek() on interactive streams, the issue you
raise is fixed on the mainline and thus will be in the 3.1 release.
As this was a performance issue only, it was not moved to the branch.

If you want to play with this, feel free to move most/all of the
mainline differences in libstdc++-v3/src/ios.cc into your 3.0 source
tree.

Regards,
Loren
-- 
Loren J. Rittle
Senior Staff Software Engineer, Distributed Object Technology Lab
Networks and Infrastructure Research Lab (IL02/2240), Motorola Labs
rittle@rsch.comm.mot.com, KeyID: 2048/ADCE34A5, FDC0292446937F2A240BC07D42763672