2013/11/23 Óscar Fuentes <[email protected]>
> Ruben Van Boxem <[email protected]>
> writes:
>
> > The libstdc++ online documentation keeps a list here:
> > http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html
> >
> > This should correspond fairly well to what is available on any platform.
> Of
> > course, there may be deviations (e.g. <thread>, and std::to_string in the
> > past). If you find any, please notify this list as it's something that
> > should be solved then :-)
>
> Thanks Ruben. Here goes the case that motivated my inquiry:
>
> The code snippet below shows that <chrono> does not work. Using
> boost::chrono yields more reasonable results.
>
>
> #include <iostream>
> #include <vector>
> #include <chrono>
>
> int main() {
> for (unsigned long long size = 1; size < 10000000; size *= 10) {
> auto start = std::chrono::steady_clock::now();
> std::vector<int> v(size, 42);
> auto end = std::chrono::steady_clock::now();
> auto elapsed = end - start;
> std::cout << size << ": " << elapsed.count() << '\n';
> }
> }
>
>
> Compiled with "g++ -std=c++11". Output:
>
> 1: 0
> 10: 0
> 100: 0
> 1000: 0
> 10000: 0
> 100000: 0
> 1000000: 15626000
>
>
> MinGW-W64 x86 g++ 4.8.2 from package
> i686-4.8.2-release-win32-dwarf-rt_v3-rev0.7z on Windows XP SP3 32bits.
>
This is comparable to the output I get from VS2013. So I would say this is
a quality of implementation issue (wrt the resolution of the clock used).
I doubt though that this is nonconformant. I didn't look up the exact
chrono requirements in the standard though.
What exactly do you think is "broken" here beyond a bad resolution?
Cheers,
Ruben
>
>
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