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How is std::function implemented?
...ally implemented by the compiler creating a class with overloaded function call operator and the referenced variables as members. This suggests that the size of lambda expressions varies, and given enough references variables that size can be arbitrarily large .
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rails 3 validation on uniqueness on multiple attributes
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In Rails 2, I would have written:
validates_uniqueness_of :zipcode, :scope => :recorded_at
In Rails 3:
validates :zipcode, :uniqueness => {:scope => :recorded_at}
For multiple attributes:
validates :zipcode, :uniqueness => {:scope => [:recor...
Difference between CC, gcc and g++?
... AIX, the system C compiler goes by names such as 'xlc' or 'xlc32'.
Classically, the default system compiler was called 'cc' and self-configuring software falls back on that name when it doesn't know what else to use.
POSIX attempted to legislate its way around this by requiring the programs c89 (...
Replacing a fragment with another fragment inside activity group
I have a fragment inside a group activity and I want to replace it with another fragment:
12 Answers
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Difference between and
...c A() {
System.out.println("creating bean A: " + this);
}
public void setBbb(B bbb) {
System.out.println("setting A.bbb with " + bbb);
this.bbb = bbb;
}
public void setCcc(C ccc) {
System.out.println("setting A.ccc with " + ccc);
this.ccc = ccc;
}
}
With the followin...
How to do 3 table JOIN in UPDATE query?
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Weird thing is however that my HeidiSQL software reports zero affected rows, although the data shows the updates were done.
– Pianoman
Feb 1 '16 at 8:06
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Is it safe to remove selected keys from map within a range loop?
...y := range (m) { if key % 2 == 0 { /* this is just some condition, such as calling expired */ delete(m, key); } }
– abanana
Jan 19 '17 at 15:40
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How to show the text on a ImageButton?
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As you can't use android:text I recommend you to use a normal button and use one of the compound drawables. For instance:
<Button
android:id="@+id/buttonok"
android:layout_width="match_parent"
android:layout_height="wrap_content...
What are the differences between Clojure, Scheme/Racket and Common Lisp?
I know they are dialects of the same family of language called lisp, but what exactly are the differences? Could you give an overview, if possible, covering topics such as syntax, characteristics, features and resources.
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What does “default” mean after a class' function declaration?
...specify that you don't want the compiler to generate that function automatically.
With the introduction of move constructors and move assignment operators, the rules for when automatic versions of constructors, destructors and assignment operators are generated has become quite complex. Using = def...