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Why does Apple recommend to use dispatch_once for implementing the singleton pattern under ARC?
...ync() is synchronous). The use of dispatch_once() replaces the following idiom:
+ (MyClass *)sharedInstance {
static MyClass *sharedInstance;
@synchronized(self) {
if (sharedInstance == nil) {
sharedInstance = [[MyClass alloc] init];
}
}
return sharedInst...
How to check whether a string contains a substring in JavaScript?
...MDN:
if (!String.prototype.includes) {
String.prototype.includes = function(search, start) {
'use strict';
if (typeof start !== 'number') {
start = 0;
}
if (start + search.length > this.length) {
return false;
} else {
return this.indexOf(search, start) !...
Embedding Base64 Images
Purely out of curiosity, which browsers does Base64 image embedding work in? What I'm referring to is this .
3 Answers
...
HTML5 check if audio is playing?
What's the javascript api for checking if an html5 audio element is currently playing?
9 Answers
...
bundle install returns “Could not locate Gemfile”
...o the gemfile in the same command e.g.
BUNDLE_GEMFILE="MyProject/Gemfile.ios" bundle install
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Why not use always android:configChanges=“keyboardHidden|orientation”?
...ing why not use android:configChanges="keyboardHidden|orientation" in every (almost every ;)) activity?
4 An...
Cannot delete directory with Directory.Delete(path, true)
...
Editor's note: Although this answer contains some useful information, it is factually incorrect about the workings of Directory.Delete. Please read the comments for this answer, and other answers to this question.
I ran into this problem before.
The root of the problem is that this fun...
How do SO_REUSEADDR and SO_REUSEPORT differ?
The man pages and programmer documentations for the socket options SO_REUSEADDR and SO_REUSEPORT are different for different operating systems and often highly confusing. Some operating systems don't even have the option SO_REUSEPORT . The WEB is full of contradicting information regarding th...
How to compile python script to binary executable
...e the issue at hand:
pyinstaller oldlogs.py
From the tool's documentation:
PyInstaller analyzes myscript.py and:
Writes myscript.spec in the same folder as the script.
Creates a folder build in the same folder as the script if it does not exist.
Writes some log files and workin...
@UniqueConstraint annotation in Java
...rite
@Column(unique=true)
String username;
The @UniqueConstraint annotation is for annotating multiple unique keys at the table level, which is why you get an error when applying it to a field.
References (JPA TopLink):
@UniqueConstraint
@Column
...