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How do BitTorrent magnet links work?
...oading/downloading a particular torrent, they try to tell each other about all of the other peers they know of that are participating in the same torrent swarm. This lets peers know of each other quickly, without subjecting a tracker or DHT to constant requests. Once you've learned of a few peers f...
java.sql.SQLException: Incorrect string value: '\xF0\x9F\x91\xBD\xF0\x9F…'
...ead:
For a supplementary character, utf8 cannot store the character at all,
while utf8mb4 requires four bytes to store it. Since utf8 cannot store
the character at all, you do not have any supplementary characters in
utf8 columns and you need not worry about converting characters or
losi...
When is std::weak_ptr useful?
...want to keep them in memory, so you hold a strong pointer to them. Periodically, you scan the cache and decide which objects have not been accessed recently. You don't need to keep those in memory, so you get rid of the strong pointer.
But what if that object is in use and some other code holds a s...
What is the id( ) function used for?
... Python objects.
Is it the same with memory addresses in C?
Conceptually, yes, in that they are both guaranteed to be unique in their universe during their lifetime. And in one particular implementation of Python, it actually is the memory address of the corresponding C object.
If yes, wh...
Optimal number of threads per core
... want to run some process in the minimum amount of time. The process is ideally parallelizable, so I can run chunks of it on an infinite number of threads and each thread takes the same amount of time.
...
Do I need elements in persistence.xml?
...k at the Chapter2. Setup and configuration too for more details.
EDIT: Actually, If you don't mind not being spec compliant, Hibernate supports auto-detection even in Java SE. To do so, add the hibernate.archive.autodetection property:
<persistence-unit name="eventractor" transaction-type="RESOUR...
Display string as html in asp.net mvc view
...n I am displaying it on views, it is displayed as simple string containing all tags.
I tried to use Html helper to encode/decode to display it properly, but it is not working.
...
How do I discover memory usage of my application in Android?
How can I find the memory used on my Android application, programmatically?
9 Answers
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Please explain some of Paul Graham's points on Lisp
...at a comparison to C and Java, which I won't do -- but for some reason I really enjoy discussing this very topic once in a while, so -- here's my shot at an answer.
On points (3) and (4):
Points (3) and (4) on your list seem the most interesting and still relevant now.
To understand them, it is usef...
find vs find_by vs where
...
Use whichever one you feel suits your needs best.
The find method is usually used to retrieve a row by ID:
Model.find(1)
It's worth noting that find will throw an exception if the item is not found by the attribute that you supply. Use where (as described below, which will return an empty arr...