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Is it intended by the C++ standards committee that in C++11 unordered_map destroys what it inserts?
...s, and move constructing it into a value_type.
That is what some people call universal reference, but really is reference collapsing. In your case, where the argument is an lvalue of type pair<int,shared_ptr<int>> it will not result in the argument being an rvalue reference and it sho...
实战低成本服务器搭建千万级数据采集系统 - 更多技术 - 清泛网 - 专注C/C++...
...法。由于有两个表作为数据插入表，使用数据库表的自增id并不太合适，需要一个高速的唯一自增Id服务器提供生成分布式ID。另数据库完全可以关闭写事务日志 ，提高性能，因为抓取的数据当时丢失再启动抓取就可以了， 这样...
What is lexical scope?
...
I understand them through examples. :)
First, lexical scope (also called static scope), in C-like syntax:
void fun()
{
int x = 5;
void fun2()
{
printf("%d", x);
}
}
Every inner level can access its outer levels.
There is another way, called dynamic scope used by...
Performant Entity Serialization: BSON vs MessagePack (vs JSON)
...checking codes.
MessagePack provides type-checking API. It converts dynamically-typed objects into statically-typed objects. Here is a simple example (C++):
#include <msgpack.hpp>
class myclass {
private:
std::string str;
std::vector<int> vec;
public:
...
Best way to reverse a string
...1/4 the way down), or the video: vimeo.com/7516539
– Callum Rogers
Apr 19 '10 at 23:14
20
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How to execute more than one maven command in bat file?
...
Use
call mvn clean
call mvn package
Note that you don't need semicolons in batch files. And the reason why you need to use call is that mvn itself is a batch file and batch files need to call each other with call, otherwise con...
Inefficient jQuery usage warnings in PHPStorm IDE
I recently upgraded my version of PHPStorm IDE and it now warns me about inefficient jQuery usage.
3 Answers
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Laravel Eloquent groupBy() AND also return count of each group
...et collection, groupBy and count:
$collection = ModelName::groupBy('group_id')
->selectRaw('count(*) as total, group_id')
->get();
Cheers!
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“Diff” an image using ImageMagick
...olution. Part of ImageMagick's v6.x software suite had a separate CLI tool called 'compare'. For v7.x of ImageMagick you should run 'magick compare' instead.
– Kurt Pfeifle
May 23 '19 at 13:19
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how does Array.prototype.slice.call() work?
...ray, but I don't understand what happens when using Array.prototype.slice.call(arguments)
13 Answers
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