STL11: Magic && Secrets

The Discussion

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  how do i watch this session on-demand?

• 

  Because of my office, I could not watch yesterday's event. I would appreciate if you share the link to watch this event. Thank you !

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  1 day ago, gotcha13 wrote

  how do i watch this session on-demand?

  Press play

  C

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  At 35:12, you start talking about move semantics in the context of the flip function taking a string by value, but there are no move semantics involved here. Since the arguments are const char arrays, the string variable s is simply initialized by the constructor string(const char*), as it always has been.

• 

  I was taking shortcuts - move semantics would have been involved if the sources were str + "stuff" - but the point still holds.

  Compare:

  flip(const string& s) { string ret(s); // #1, reverse and return ret

  versus:

  flip(string s) { // #2, reverse and return s

  Given flip("meow"), #1 creates a temporary string, binds the const reference s to it, then (unnecessarily!) copies it into ret. #2 constructs s from "meow", as you mentioned, then flips and move-returns it.

  So, #2 made sense even in C++98/03, and it plays nice with move semantics.

• 

  Great talk, it's always a joy to hear you talking! I hope you'll have a little bit more time for your Advanced STL series once VS11 is out.

  Then, any particular reason that nearly every slide was titled with a TVTrope?

  (Also, can we get access to these slides?)

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  What are cars, putters and stoods??!

• 

  2 days ago, STL wrote

  Compare:

  flip(const string& s) { string ret(s); // #1, reverse and return ret

  versus:

  flip(string s) { // #2, reverse and return s

  Given flip("meow"), #1 creates a temporary string, binds the const reference s to it, then (unnecessarily!) copies it into ret. #2 constructs s from "meow", as you mentioned, then flips and move-returns it.

  So, #2 made sense even in C++98/03, and it plays nice with move semantics.

  So, when we have a C++ class X and we want to modify a copy of it inside a function/method, does it make sense (also in C++98/03) to always use signature like your #2? i.e.

  DoSomething( X x )

  instead of the more usual DoSomething(const X &) ?

  Thanks.

   

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  Audio, at least on the "High Quality MP4", is out of sync with the video. Either that or STL can add ventriloquism to his already impressive list of skills and credentials ;-)
  
  Haven't downloaded the other qualities, maybe it's just the HQ MP4. FWIW, I downloaded the other videos, this seems to be the only one that's buggered.
  
  Thanks for making the videos & slides for the talks available, much appreciated. The only problem is that now I regret even more not being able to attend :-(

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  By "downloaded the other videos", I meant the other talks, sorry if that wasn't clear...

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  1 hour ago

  By "downloaded the other videos", I meant the other talks, sorry if that wasn't clear...

  Thank you, Dan. I noticed that too (when the file was intitially released). It was re-encoded to hopefully fix the HQ MP4 audio sync issue. Looks like it didn't work
  
  We'll figure it out.

  C

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  c9xeo> Great talk, it's always a joy to hear you talking!

  Thanks!

  c9xeo> I hope you'll have a little bit more time for your Advanced STL series once VS11 is out.

  Me too. You can think of this as "Advanced STL, Part Infinity" for the time being. :->

  c9xeo> Then, any particular reason that nearly every slide was titled with a TVTrope?

  I came up with "Twenty Minutes Into The Future" and "The Reveal" first, and I liked them so much, I had to follow the pattern. :->

  c9xeo> (Also, can we get access to these slides?)

  The links are above: "Slides (view online)"

  someone> What are cars, putters and stoods??!

  I pronounce "char", "ptr", and "std" as "care" (it's the prefix of "character"), "putter", and "stood".

  C64> So, when we have a C++ class X and we want to modify a copy of it inside a function/method, does it make sense (also in C++98/03) to always use signature like your #2?

  Yes. It's sometimes better, and never worse. The advantage increases in C++11, but is present in C++98/03.

• 

  (never mind)

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  As always i enjoy reading this awesome content, i hope you can find as much enjoyable content from me in return.

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  > Me too. You can think of this as "Advanced STL, Part Infinity" for the time being. :->

  Heh, topic suggestion: Template meta programming! With things like Expression SFINAE, writing ones own type traits (like how to find out if a class has a certain member function), like you did in part 5 of Advanced STL.

  Maybe also about constexpr? But that isn't implemented in VS, right?

  Hmm, what else... I'll think about it some more and report back.

  Edit: Oooh, another idea! I know this doesn't really count as STL, since they don't belong in that subpart of the library, but what about IOstreams? Especially the streambufs, locales, facets, codecvt stuff. As far as I know, there's only one real book on IOstreams, and it's from 2000 (IIRC). And personally, I think IOstreams are one of the more advanced topics, if you go beyond simple streaming to existing streams.

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  Hi guys,

  I just wanna ask you guys, what question did Bjarne Stroustrup ask during the last few minutes? I didn't hear it clearly 

• 

   

  c9xeo> Heh, topic suggestion: Template meta programming!

   

  I am definitely thinking I'll do a "Core C++" series, including TMP but also template argument deduction, overload resolution, name lookup, etc.

   

  > With things like Expression SFINAE

   

  That's not yet supported by VC in full generality, but Herb announced post-VC11 "out of band" releases, where new features will appear. 

   

  > Maybe also about constexpr? But that isn't implemented in VS, right?

   

  Correct. constexpr is a very, very big feature. 

   

  > what about IOstreams? 

   

  iostreams fills me with dread and loathing. Maintaining the stuff is just about all I can handle.

   

  haohaolee> I just wanna ask you guys, what question did Bjarne Stroustrup ask during the last few minutes?

   

  IIRC, whether I would define NULL to be nullptr. I said yes if I had a time machine, no otherwise. 

  
  

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  > I am definitely thinking I'll do a "Core C++" series

  Yes, please!

  > iostreams fills me with dread and loathing. Maintaining the stuff is just about all I can handle.

  Then make it a "Bash the IOstreams" session? Tell us what's so horrible about them!

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  @STL

  Thanks

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  Here is the future sample code:

  string flip(string s) {   

  reverse(begin(s), end(s));

   return s;

  }

  vector<future<string>> v;

  v.push_back(async( [] {return flip(" ,gnol oS"); }));

  v.push_back(async( [] {return flip(" dlrow"); }));

  v.push_back(async( [] {return flip("\n.ti wonk ew sa"); }));

  for(auto& e : v) { cout << e.get(); }

   

  Thanks,

  Comet

  purr more, hiss less

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  Feb 10, 2012 at 7:43 PM, c9xeo wrote

  > I am definitely thinking I'll do a "Core C++" series

  Yes, please!

  > iostreams fills me with dread and loathing. Maintaining the stuff is just about all I can handle.

  Then make it a "Bash the IOstreams" session? Tell us what's so horrible about them!

  The Core C++ series has begun: https://channel9.msdn.com/Shows/Going+Deep/Stephan-T-Lavavej-Core-C-1-of-n

  STL rocks!
  C

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  What is matter your eyes?