C++標準化委員会の文書: P0399R0-P0515R2

[PDF] P0399R0: Networking TS & Threadpools


[PDF] P0424R1:Reconsidering literal operator templates for strings

文字列リテラルに対するユーザー定義演算子で文字列を(harT const *, std::size_t)で取れるようにする提案。

template < typename CharT, CharT const * str, std::size_t length >
auto operator "" _udl() ;

auto x = "abcd"_udl ;

[PDF] P0429R2:A Standard flat_map




P0443R3:A Unified Executors Proposal for C++


P0447R4: Introduction of std::colony to the standard library



std::vector v = {1,2,3,4,5} ;
// 中間の要素を削除
v.erase( v.begin()+2 ) ;




なお、リファレンス実装では、無効要素の読み飛ばしは要素ごとに無効フラグを持つのでもなく、ビットマップで無効フラグを持つのでもなく、jump-counting skipfieldと呼ばれる手法を用いるらしい。これによって連続した無効要素を読み飛ばすのがキャッシュ効率よく行えるそうだ。

The Advanced “Jump-Counting” Skipfield Pattern

[PDF] P0461R2: Proposed RCU C++ API


P0479R2: Attributes for Likely and Unlikely Statements



if ( is_error )
[[ unlikely]] {
// めったに起こらないエラー

GCCとClangは独自拡張として__builtin_expectという同等機能のcompiler intrinsicsを提供している。MozillaやChromiumのような現実のコードでも使用されている。


[PDF] P0506R2: use string_view for library function parameters instead of const string & / const char *

string_viewを標準ライブラリで文字列を受け取る引数の型として積極的に使っていこうという提案。std::string const &やchar const *で受け取るよりよい。

[PDF] P0514R2:Efficient waiting for concurrent programs


[PDF] P0515R2:Consistent comparison

C++における比較をより厳密にするための新しい演算子、operator <=>の提案。

operator <=>(a, b)はa, bの大小関係と等号関係に応じて適切な3値のいずれかを返す。また、strong order, weak order, partial order, strong equality, weak equalityも型で表現する。





CC BY-ND 4.0: Creative Commons — Attribution-NoDerivatives 4.0 International — CC BY-ND 4.0


abo_junghichi said...

> なお、リファレンス実装では、無効要素の読み飛ばしは要素ごとに無効フラグを持つのでもなく、ビットマップで無効フラグを持つのでもなく、jump-counting skipfieldと呼ばれる手法を用いるらしい。これによって連続した無効要素を読み飛ばすのがキャッシュ効率よく行えるそうだ。


It stores and modifies (during insertion and erasure) numbers which correspond to the number of elements in runs of consecutive erased elements, and during iteration uses these numbers to skip over the runs. This avoids the looping branch code necessary for iteration with a boolean skipfield - which is slow, but which also cannot be used due to it's O(random) time complexity.

"次の有効要素番号 = 現在の要素番号 + (読み飛ばす要素数) + 1"

opbest said...

Excellent post. I was checking continuously this
blog and I am impressed! Extremely helpful information specifically the last part :
) I care for such information much. I was seeking this particular
info for a long time. Thank you and best of luck.

my blog post ==== 오피사이트


majortotositepro said...

I savour, lead to I found exactly what I used to be having a look for. You’ve ended my four day long hunt! God Bless you man. Have a nice day. Bye 메이저사이트

racesitepro said...

I used to be suggested this blog through my cousin. I’m no longer sure whether this submit is written through him as
nobody else understand such detailed approximately my trouble.
You’re wonderful! Thank you! 온라인경마

oncasinositenet said...

I really enjoyed this blog post, thank you for sharing it. I’ll return for more. See you soon! 카지노

totopickpro said...

This paragraph will help the internet visitors for building up new web site or even a weblog from start to end. 토토

oncasinosite said...

It was a very good post indeed. I thoroughly enjoyed reading it in my lunch-time. I Will surely come and visit this blog more often. Feel free to visit my website; 온라인카지노

casinositelink said...

Wow, awesome blog layout! How long have you been blogging for? you make blogging look easy. The overall look of your web site is great, as well as the content!Feel free to visit my website; 온라인카지노

oncasinositenet said...

Very informative and well-written post! The quite interesting and nice topic chosen for the post. thankyou Feel free to visit my website; 바카라사이트

bacarasite said...

Wonderful items from you, man. I’ve have in mind your stuff previous to and you’re just extremely excellent. I actually like what you’ve acquired here, really like what you’re saying and the way in which through which you assert it. You’re making it entertaining and you still care for to keep it smart. I cant wait to read far more from you. That is actually a terrific web site Also visit my website: 온라인카지노

casinoonline said...

Why couldn't I have the same or similar opinions as you? T^T I hope you also visit my blog and give us a good opinion.casino online