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Spinlock versus Semaphore
...ossible implementation of a lock, namely one that is implemented by busy waiting ("spinning"). A semaphore is a generalization of a lock (or, the other way around, a lock is a special case of a semaphore). Usually, but not necessarily, spinlocks are only valid within one process whereas semaphores c...
Which is more efficient, a for-each loop, or an iterator?
...on to read all of the values, then there is no difference between using an iterator or the new for loop syntax, as the new syntax just uses the iterator underwater.
If however, you mean by loop the old "c-style" loop:
for(int i=0; i<list.size(); i++) {
Object o = list.get(i);
}
Then the ne...
Hidden features of Python [closed]
...; x <= 9
True
>>> 5 == x > 4
True
In case you're thinking it's doing 1 < x, which comes out as True, and then comparing True < 10, which is also True, then no, that's really not what happens (see the last example.) It's really translating into 1 < x and x < 10, and x <...
What is the use of printStackTrace() method in Java?
I am going through a socket program. In it, printStackTrace is called on the IOException object in the catch block.
What does printStackTrace() actually do?
...
Use 'import module' or 'from module import'?
I've tried to find a comprehensive guide on whether it is best to use import module or from module import . I've just started with Python and I'm trying to start off with best practices in mind.
...
How to find memory leak in a C++ code/project?
...ory only if you've deleted. In the code below, str acquires a new address with the second allocation. The first address is lost irretrievably, and so are the 30 bytes that it pointed to. Now they're impossible to free, and you have a memory leak:
char* str = new char [30]; // Give str a memory addr...
no gravity for scrollview. how to make content inside scrollview as center
...
I had the same issue and finally figured it out. This is for a vertical ScrollView.
Put your ScrollView inside a RelativeLayout and center it in the RelativeLayout. In order for this to work, your ScrollView should have
android:layout_height="wrap_content"
Thi...
Difference between Key, Primary Key, Unique Key and Index in MySQL
...users and you want to search for all the users which have the last name 'Smith'. Without an index, the database would have to go through all the records of the table: this is slow, because the more records you have in your database, the more work it has to do to find the result. On the other hand, a...
Is it possible to listen to a “style change” event?
Is it possible to create an event listener in jQuery that can be bound to any style changes? For example, if I want to "do" something when an element changes dimensions, or any other changes in the style attribute I could do:
...
How do I restore a dump file from mysqldump?
...
It should be as simple as running this:
mysql -u <user> -p < db_backup.dump
If the dump is of a single database you may have to add a line at the top of the file:
USE <database-name-here>;
If it was a du...