runtime | 易学教程

Why annotations written in Scala are not accessible at runtime?

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问题 I have come across a statement in scalatest documentation: It must be defined in Java instead of Scala so it will be accessible at runtime. This is quite weird as I was under the impression that Scala annotation is stronger than its Java counterpart. Why this feature is missing? Is there a plan to add it back? 回答1: There is no known plan to have Scala support annotations retained at runtime (the issue has been known for a while but as this page says, it won't be fixed). Lukas Rytz, a Scala

Can an app give its permission to another application in android?

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问题 I have an application say A that have all the permissions enabled at installation. Another app Say B don't have a permission and want to get that permission. Can B communicate with A, So that A can transfer its permission to B. PLS reply, I'm stuck here. I want to get some permissions dynamically. Is this the best idea or any other idea? 回答1: As far as I know, apps can't necessarily give permissions to other apps, BUT AppB could inherit permissions from AppA IF you are the developer of both

Any way to extract underlying Xaml?

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问题 Is there anyway to extract the underlying xaml from a control. IE. I have a textbox named fooBox. Can I get xaml back from the textbox at runtime that represents the textbox? 回答1: This shows you the full lifecycle (from control to XAML back to control). As you can see, string s = XamlWriter.Save(value); is the interesting part you might care about. /// <summary> /// Clones a given UIElement. Please note that any events, animations, etc /// on the source item may not carry over to the cloned

how does the undecided generic type represents in ghci's runtime

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问题 I'm clear about the generic functions and generic data-types. In the generic type: data SB = forall x. (show x) => SB x instance Show SB where show (SB x) = show x so for any given type x , if it has a signature of Show , and there sure be a show function corresponds to it. but when typing in ghci, e.g. :t 1 outputs 1 :: Num a => a if binds 1 to a name: let a=1 :t a now a has a true type. The question is: What is 1 's form in the run-time system (before it has a type, it has only Num ) ,

Debugging the C runtime

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问题 I want to get a detailed look at what's going on both before and after main() using GDB. Would it be enough just to recompile glibc with -g and link against that? 回答1: if you want to play with the debugger, you can use GDB this way: install the debug-info for the `glibc` package (here is the way to do it with Fedora, I don't know about the other distros) or point GDB to a consistent debug file directory: (gdb) show debug-file-directory The directory where separate debug symbols are searched

Runtime Transform Gizmos丨功能实现

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一、前言： Runtime Transform Gizmos已有介绍很详细的博客。因此本章不再介绍基础功能了。转而实现拓展功能。二、基础配置：参考博客：链接三、拓展功能 1、实现按下某按钮，选中某些物体效果：代码： EditorObjectSelection 脚本添加如下代码：（ untiy按键键值表） [DllImport("user32.dll", EntryPoint = "keybd_event")] public static extern void Keybd_event( byte bvk,//虚拟键值 ESC键对应的是27 byte bScan,//0 int dwFlags,//0为按下，1按住，2释放 int dwExtraInfo//0 ); public void Skode_Press() { _selectedObjects.Clear(); _selectedObjects.Add(GameObject.Find("Cube")); _selectedObjects.Add(GameObject.Find("Cube (1)")); _selectedObjects.Add(GameObject.Find("Cube (2)")); //模拟W键按下、松开。 Keybd_event(87, 0, 0, 0); Keybd_event(87

Determining if an Objective-C method is variadic during runtime

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问题 Is there a way to find out -- at runtime -- whether a given method is of variadic type? Something like method_getTypeEncoding() ; that won't tell me whether a method accepts variable number of arguments. Or is there maybe a trick to tell so? 回答1: Robert's comment is correct. Consider: @interface Boogity @end @implementation Boogity - (void)methodWithOneIntArg:(int)a {;} - (void)variadicMethodWithIDSentinel:(id)a, ... {;} @end Running strings on the resulting binary produces (there was also

Determining if an Objective-C method is variadic during runtime

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docker学习_1、容器生态系统

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container ecosystem 容器生态系统，思维导图自己的小理解，仅作为捋思路使用。容器技术的背景、基础结构 contrainer ecosystem Kernel Platform Suport 容器生态主要分为三块大的组成，核心技术、平台、支持技术 Kernel Container specification Container runtime Container manager Container definition Registry Container OS Runtime spec Image format spec lxc runc rkt lxd docker engine rkt cli docker image dockerfile ACI:app container image docker registry docker hub ..... core os ubuntu core 核心技术为了一个大目标：应用环境的更广、更适用 specification：标准是基础，统一容器的标准，好似usb接口取代了许多电脑接口，来源于标准化，主要使runtime和image进行标准化。 runtime：容器运行的环境。 lxd：原docker默认的runtime，来源于Linux。 runc：docker自己开发的runtime，先docker默认。

【MySQL】【ProxySQL】ProxySQL Cluster的搭建

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背景：早期的ProxySQL若需要做高可用，需要搭建两个实例，进行冗余。但两个ProxySQL实例之间的数据并不能共通,在主实例上配置后，仍需要在备用节点上进行配置，对管理来说非常不方便。从1.4.2版本后，ProxySQL支持原生的集群搭建，实例之间可以互通一些配置数据，大大简化了管理与维护操作。环境：实例名版本 IP 系统备注 ProxySQL 1 1.4.6 208 CentOS7 最初启动 ProxySQL 2 1.4.6 209 CentOS7 最初启动 ProxySQL 3 1.4.6 210 Debian9 后面加入搭建：集群的搭建有很多种方式，如1+1+1的方式，还可以(1+1)+1的方式。这里采用较简单的(1+1)+1，即先将两个节点作为集群启动，然后其他节点选择性加入的方式 1.更改所有实例的配置文件： vim /etc/proxysql.cnf # 需要更改的部分 admin_variables= { admin_credentials="admin:admin;cluster_20X:123456" #配置用于实例间通讯的账号 # mysql_ifaces="127.0.0.1:6032;/tmp/proxysql_admin.sock" mysql_ifaces="0.0.0.0:6032" #全网开放登录 #