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How to make a class property? [duplicate]
...baz.bar == 50
assert foo.bar == 50
The setter didn't work at the time we call Bar.bar, because we are calling
TypeOfBar.bar.__set__, which is not Bar.bar.__set__.
Adding a metaclass definition solves this:
class ClassPropertyMetaClass(type):
def __setattr__(self, key, value):
if key...
What is meant with “const” at end of function declaration? [duplicate]
...) results in a function like int Foo_Bar(Foo* this, int random_arg), and a call such as Foo f; f.Bar(4) will internally correspond to something like Foo f; Foo_Bar(&f, 4). Now adding the const at the end (int Foo::Bar(int random_arg) const) can then be understood as a declaration with a const th...
How can I disable logging of asset pipeline (sprockets) messages in Ruby on Rails 3.1?
...ger=, Logger.new('/dev/null'))
Rails::Rack::Logger.class_eval do
def call_with_quiet_assets(env)
previous_level = Rails.logger.level
Rails.logger.level = Logger::ERROR if env['PATH_INFO'] =~ %r{^/assets/}
call_without_quiet_assets(env)
ensure
Rails.logger.level = pr...
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...IFO、LRU、LFU都是比较经典的换页算法。相关内容参看Wikipeida的缓存算法。
3）缓存的重建和持久化。缓存在内存，系统总要维护，所以，缓存就会丢失，如果缓存没了，就需要重建，如果数据量很大，缓存重建的过程会很慢，这...
ssh: connect to host github.com port 22: Connection timed out
...ed.
For me I am getting this error on my AWS EC2 UBUNTU instance, what I did to resolve it was to edit the ssh config (or add it if it does not exist).
sudo nano ~/.ssh/config
And I added the following
Host github.com
Hostname ssh.github.com
Port 443
Then, run the command ssh -T git@github.c...
Get properties and values from unknown object
...nts the type (at runtime) of the instance in the list. You can do this by calling the GetType method on Object. Because it is on the Object class, it's callable by every object in .NET, as all types derive from Object (well, technically, not everything, but that's not important here).
Once you ha...
What is the difference between exit(0) and exit(1) in C?
...
@CatPlusPlus: On OpenVMS, calling exit with any odd value denotes success. exit(0) is treated as a special case for the sake of C conformance. Yes, POSIX is a standard, but not all systems conform to it. If you want to write code that assumes POSIX, y...
How to know what the 'errno' means?
When calling execl(...) , I get an errno=2 . What does it mean? How can I know the meaning of this errno ?
15 Answers
...
filename and line number of python script
...
@gsinha: Every function call has performance impact. You have to measure if this impact is acceptable for you.
– omikron
Nov 9 '15 at 14:45
...
Is there a performance difference between i++ and ++i in C++?
...
However, if i is an instance of a C++ class, then i++ and ++i are making calls to one of the operator++ functions. Here's a standard pair of these functions:
Foo& Foo::operator++() // called for ++i
{
this->data += 1;
return *this;
}
Foo Foo::operator++(int ignored_dummy_value) ...