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What does -D_XOPEN_SOURCE do/mean?
...t;some number>
it tells your compiler to include definitions for some extra functions that are defined in the X/Open and POSIX standards.
This will give you some extra functionality that exists on most recent UNIX/BSD/Linux systems, but probably doesn't exist on other systems such as Windows.
...
Why is sizeof considered an operator?
...operator rather than a function. For instance:
union foo {
int i;
char c[sizeof(int)];
};
Syntactically if it weren't an operator then it would have to be a preprocessor macro since functions can't take types as arguments. That would be a difficult macro to implement since sizeof can take...
PHP function to get the subdomain of a URL
...rk in almost all cases, be aware that domains names might have more than 6 chars, like pvt.k12.ma.us, health.vn or even k12.ak.us. Also, domains names may be use Chinese or Russian character set so the regex part [a-z\.]{2,6} would not match them. Check out here to have example domains name: publics...
PHP: Storing 'objects' inside the $_SESSION
...on objects based on the ID the client submitted with the request. All this extra work is a double whammy on scalability (a big reason HTTP is stateless).
Whammy One: It reduces the work a single server can do.
Whammy Two: It makes it harder to scale out because now you can't just route a request t...
Looking for a clear definition of what a “tokenizer”, “parser” and...
...hes extra context to the tokens -- this token is a number, that token is a string literal, this other token is an equality operator.
A parser takes the stream of tokens from the lexer and turns it into an abstract syntax tree representing the (usually) program represented by the original text.
Las...
How do MySQL indexes work?
...lision number is high cause you'll only perform the second comparison (the string one) against the repeated hashes.
Unfortunately, using this technique, you still need to hit the table to compare the url field.
Wrap up
Some facts that you may consider every time you want to talk about optimizatio...
Remove elements from collection while iterating
...
Old Timer Favorite (it still works):
List<String> list;
for(int i = list.size() - 1; i >= 0; --i)
{
if(list.get(i).contains("bad"))
{
list.remove(i);
}
}
Benefits:
It only iterates over the list once
No extra objects ...
Passing Parameters JavaFX FXML
...age;
public class Main extends Application {
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) {
// Create the first controller, which loads Layout1.fxml within its own constructor
Controller1 controll...
Best way to determine user's locale within browser
...er and spits it back out as a JavaScript file with the header value in the string, eg.:
var acceptLanguage= 'en-gb,en;q=0.7,de;q=0.3';
then you could include a <script src> pointing at that external service in the HTML, and use JavaScript to parse the language header. I don't know of any ex...
How to insert element into arrays at specific position?
... @roelleor But be careful: "If the input arrays have the same string keys, then the later value for that key will overwrite the previous one. If, however, the arrays contain numeric keys, the later value will not overwrite the original value, but will be appended." - array_merge
...