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Programmatically find the number of cores on a machine
...ine, if a system is capable of turning some off they might not be counted. Calling sysconf with "_SC_NPROCESSORS_CONF" will return the total CPUs configured.
– Chris S
Apr 23 '11 at 18:43
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What's the difference between the atomic and nonatomic attributes?
...o no need to declare instance variables; they will be synthesized automatically, too, and will have an _ prepended to their name to prevent accidental direct access).
With "atomic", the synthesized setter/getter will ensure that a whole value is always returned from the getter or set by the setter...
Introducing FOREIGN KEY constraint may cause cycles or multiple cascade paths - why?
...ou forgot the builder _ .Entity<TEntity>() _ before HasOne() can be called...
– ViRuSTriNiTy
May 18 at 13:51
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Convert .pem to .crt and .key
...about that.
openssl genrsa -out private.pem 1024
This creates a key file called private.pem that uses 1024 bits. This file actually have both the private and public keys, so you should extract the public one from this file:
openssl rsa -in private.pem -out public.pem -outform PEM -pubout
or
ope...
PHP session lost after redirect
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First, carry out these usual checks:
Make sure session_start(); is called before any sessions are being called. So a safe bet would be to put it at the beginning of your page, immediately after the opening <?php declaration before anything else. Also ensure there are no whitespaces/tabs b...
Combining node.js and Python
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We are highly concerned about speed, what is the most elegant way how to call a Python "worker" from node.js in an asynchronous non-blocking way?
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What is the difference between Trap and Interrupt?
...emory access. It's also the usual way to invoke a kernel routine (a system call) because those run with a higher priority than user code. Handling is synchronous (so the user code is suspended and continues afterwards). In a sense they are "active" - most of the time, the code expects the trap to ha...
What is an idempotent operation?
...ing, an idempotent operation is one that has no additional effect if it is called more than once with the same input parameters. For example, removing an item from a set can be considered an idempotent operation on the set.
In mathematics, an idempotent operation is one where f(f(x)) = f(x). For ex...
Accessing outside variable using anonymous function as params
Basically I use this handy function to processing db rows (close an eye on PDO and/or other stuff)
2 Answers
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Python extending with - using super() Python 3 vs Python 2
...ass__, self), but that is wrong. If Class2 inherits from Class1 and Class1 calls super(self.__class__, self).__init__(), Class1's __init__ will then call itself when instantiating an instance of Class2.
– jpmc26
Jul 15 '15 at 18:10
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