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How can I calculate the difference between two dates?
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Not all days have 86400 seconds. For a trivial example that's fine but it's not a good idea in the real world. DST changes, leap seconds, etc can all mess with it. NSCalendar can tell you how many seconds are in a given day.
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When to use volatile with multi threading?
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However two threads both accessing a shared variable is something which calls for protection via a mutex isn't it?
But in that case, between the thread locking and releasing the mutex the code is in a critical section where only that one thread can access the variable, in which case the variable ...
How does the bitwise complement operator (~ tilde) work?
...ng the binary representation of a number, taking its complement (inverting all the bits) and adding one. Two starts as 0000 0010, and by inverting the bits we get 1111 1101. Adding one gets us the result above. The first bit is the sign bit, implying a negative.
So let's take a look at how we get ~2...
How to configure PostgreSQL to accept all incoming connections
I've got a PostgreSQL data base that I'd like to configure to accept all incoming connections regardless of the source IP address. How can this be configured in the pg_hba.conf file? I'm using postgreSQL version 8.4.
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Can I change the viewport meta tag in mobile safari on the fly?
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I realize this is a little old, but, yes it can be done. Some javascript to get you started:
viewport = document.querySelector("meta[name=viewport]");
viewport.setAttribute('content', 'width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0');
Just change the parts you ...
Is 23,148,855,308,184,500 a magic number, or sheer chance?
...thel, and a teenage girl, Elizabeth Lewis in Owatonna .
The thing is that all of them have the exact same charge: $23,148,855,308,184,500.00. If the problem was the space-padding, then how is it that all of them had the exact same $0x1250 ($46.88) charge? Two of them had purchased cigarettes at gas...
Why am I getting error for apple-touch-icon-precomposed.png
...means the configured web document-root directory, e.g. in Apache 2.4 it usually /var/www/htdocs
– Hgehlhausen
Dec 14 '16 at 19:40
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Remove non-utf8 characters from string
...eplacement is whatever was captured into group 1. This effectively removes all invalid bytes.
It is possible to repair the string, by encoding the invalid bytes as UTF-8 characters. But if the errors are random, this could leave some strange symbols.
$regex = <<<'END'
/
(
(?: [\x00-...
Uses of Action delegate in C# [closed]
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Here is a small example that shows the usefulness of the Action delegate
using System;
using System.Collections.Generic;
class Program
{
static void Main()
{
Action<String> print = new Action<String>(Program...
Create a string of variable length, filled with a repeated character
...slower than a string-concatenation-based implementation. It performs especially badly on large strings. See below for full performance details.
On Firefox, Chrome, Node.js MacOS, Node.js Ubuntu, and Safari, the fastest implementation I tested was:
function repeatChar(count, ch) {
if (count == ...