runtime

Boost spirit takes for ever to parse expressions

由 怎甘沉沦 提交于 2019-12-23 16:24:47
问题 i am new here working with boost spirit Reading alot of very good articels for boost Spirit i decide to make an own Parser and run into the Problem that parsing an Expression like this 1+(2+(3+(4+(5+(6+(7+(8))))))) takes forever on runtime.. making it more simple 1+(2+(3)) works fine. I Looks like the backtracking of the Parser is active. Please give me a hint how to modify the grammer or behaviour to make this run in time. Here is a bit code from the grammer. I use the "iter_pos" for

Set .Net 4 'useLegacyV2RuntimeActivationPolicy' during runtime?

由 橙三吉。 提交于 2019-12-23 15:03:50
问题 Is it possible to set the app.config useLegacyV2RuntimeActivationPolicy parameter during runtime (basically before one of the 'affected' assemblies is being loaded?). 回答1: This can be done via the CLR Hosting APIs. I detail the technique here. 来源： https://stackoverflow.com/questions/3750253/set-net-4-uselegacyv2runtimeactivationpolicy-during-runtime

redis string hash 测试

由 核能气质少年 提交于 2019-12-23 14:01:39
//$num = 30*200; $num = 50000; $stratTime = microtime(true); $startMemory = memory_get_usage(); for($i=0;$i<$num;$i++){ $array = array( 'zero'=>'resty'.$i,'one'=>'onetht'.$i,'two'=>'this is test'.$i,'three'=>3+$i,'four'=>4); $arrayString = json_encode($array); $this->redis->set('onetest'.$i,$arrayString); $getRedis = $this->redis->get('onetest'.$i); $tmp = json_decode($getRedis,true); } $endTime = microtime(true); $runtime = ($endTime - $stratTime) * 1000; //将时间转换为毫秒 $endMemory = memory_get_usage(); $usedMemory = ($endMemory - $startMemory) / 1024; echo "运行时间: {$runtime} 毫秒<br />"; echo "耗费内存:

Oddities in runtime evaluation of static variable initializers when debugging

由 一个人想着一个人 提交于 2019-12-23 13:41:18
问题 My App was running fine when I started it from inside Visual Studio with the debugger attached (F5). But when I started the App without attaching the debugger (Ctrl-F5 or starting the .exe file) i did always get a StackOverflowException which was luckily logged in the Windows event logs. The problematic code was the following: namespace Caliburn.Micro.Contrib { public static class FrameworkExtensions { public static class ViewLocator { static readonly Func<string,object, IEnumerable<string>>

Delphi - Creating MySQL database at runtime

由 ╄→尐↘猪︶ㄣ 提交于 2019-12-23 13:09:17
问题 I have a delphi application which connects to MySQL database, however, I would like to give create an easy way for my end user to implement the MySQL database. I thought about creating a button within my application which the user could press to delete any current instances of the scehma, and create a new schema with the correct tables and columns which my application requires to function. I have written the code to create the new database. It is as follows: CREATE SCHEMA IF NOT EXISTS

Are objective-c objects all same type of C-structure?

由 孤人 提交于 2019-12-23 12:28:43
问题 I want to know how the language's object-oriented features are implemented in C. As defined in <objc/runtime.h> , id type is a pointer to a objc_object , and objc_object type is a C-structure with only one member isa storing a Class . Then where and how are the actual values of any object's instance-variables stored? One more thing, the fact that all objective-C object-pointers can be casted to id (which is a pointer to a C-structure, where no feature such as inheritance exists), are

unloading php extensions : reverse dl()

由 落花浮王杯 提交于 2019-12-23 12:23:09
问题 To you gurus out there, is there any hidden gem in PHP that could unload a specific extension at runtime ? 回答1: No, that's not possible and most likely never will: [2011-02-08 11:34 UTC] rasmus@php.net extension unloading on a per-request basis simply isn't feasible from a performance point of view. And you obviously can't unload and leave it unloaded for the next request because that next request may be for a page that expects the extension to be there. However, using dl() is discouraged

Java raw type value assigned to generic type run time getClss() method error

由 倾然丶 夕夏残阳落幕 提交于 2019-12-23 10:59:41
问题 public class Box<T> { private T t; public Box(T t){ this.t = t; } public void add(T t) { this.t = t; } public T get() { return t; } public static void main(String[] args) { Box<Integer> b = new Box(new String("may be")); System.out.println(b.get()); // successfully print out "may be" System.out.println(b.get().getClass()); // error } } This code gives a runtime error: exception in thread "main" java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer why is b.get()

What's the limit to the number of members you can have in a java enum?

由 人走茶凉 提交于 2019-12-23 09:05:15
问题 Assuming you have a hypothetical enum in java like this (purely for demonstration purposes, this isn't code i'm seriously expecting to use): enum Example{ FIRST, SECOND, THIRD, ... LAST; } What's the maximum number of members you could have inside that enum before the compiler stops you? Secondly, is there any performance difference at runtime when your code is referencing an enum with say, 10 members as opposed to 100 or 1,000 (other than just the obvious memory overhead required to store

Bounds Checking in Java

由 核能气质少年 提交于 2019-12-23 07:27:42
问题 "Hotspot can remove bounds checking in Java." Can any one explain this please? Actually im analysing the differences between C++ and Java. It is not a homework and im analysing on my own interest. 回答1: After googling "hotspot bounds checking", a Paper with the Title "Array Bounds Check Elimination for the Java HotSpot™ Client Compiler" shows up (as the first result) and gives us some insight: Abstract: Whenever an array element is accessed, Java virtual machines execute a compare instruction
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