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Are Swift variables atomic?
... you, i.e.:
class Car {
static let sharedCar: Car = Car() // will be called inside of dispatch_once
}
private let sharedCar: Car2 = Car2() // same here
class Car2 {
}
Update 05/25/16: Keep an eye out for swift evolution proposal https://github.com/apple/swift-evolution/blob/master/proposals...
ObservableCollection not noticing when Item in it changes (even with INotifyPropertyChanged)
...
The ContentList's Set method will not get called when you change a value inside the collection, instead you should be looking out for the CollectionChanged event firing.
public class CollectionViewModel : ViewModelBase
{
public ObservableCollection<E...
Circle line-segment collision detection algorithm?
... exdx + eydy - dxh - dyk ) +
ex2 + ey2 -
2exh - 2eyk + h2 + k2 - r2 = 0
Finally,
t2( _d * _d ) + 2t( _e * _d - _d * _c ) + _e * _e - 2( _e*_c ) + _c * _c - r2 = 0
*Where _d is the vector d and * is the dot product.*
And then,
t2( _d * _d ) + 2t( _d * ( _e - _c ) ) + ( _e - _c ) * ( _e - _c ) - r2 = ...
How to search a specific value in all tables (PostgreSQL)?
... at 11:55
Mike Sherrill 'Cat Recall'Mike Sherrill 'Cat Recall'
78.5k1616 gold badges103103 silver badges156156 bronze badges
...
Which commit has this blob?
... scripts take the blob’s SHA1 as the first argument, and after it, optionally, any arguments that git log will understand. E.g. --all to search in all branches instead of just the current one, or -g to search in the reflog, or whatever else you fancy.
Here it is as a shell script – short and sw...
When to use NSInteger vs. int
...
You usually want to use NSInteger when you don't know what kind of processor architecture your code might run on, so you may for some reason want the largest possible integer type, which on 32 bit systems is just an int, while on a ...
convert UIImage to NSData
...ata* data = (id)CFBridgingRelease(CGDataProviderCopyData(provider));
const uint8_t* bytes = [data bytes];
This will give you the low-level representation of the image RGB pixels.
(Omit the CFBridgingRelease bit if you are not using ARC).
...
Why should I prefer to use member initialization lists?
...tyle. For class members which are classes, then it avoids an unnecessary call to a default constructor. Consider:
class A
{
public:
A() { x = 0; }
A(int x_) { x = x_; }
int x;
};
class B
{
public:
B()
{
a.x = 3;
}
private:
A a;
};
In this case, the construct...
Are static class variables possible in Python?
... if it's a subclass. A static method lacks this information, so it cannot call an overridden method, for example.
– Seb
Oct 2 '12 at 15:58
...
Is there a standard sign function (signum, sgn) in C/C++?
...T val) {
return (T(0) < val) - (val < T(0));
}
Benefits:
Actually implements signum (-1, 0, or 1). Implementations here using copysign only return -1 or 1, which is not signum. Also, some implementations here are returning a float (or T) rather than an int, which seems wasteful.
Works ...