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performSelector may cause a leak because its selector is unknown
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Solution
The compiler is warning about this for a reason. It's very rare that this warning should simply be ignored, and it's easy to work around. Here's how:
if (!_controller) { return; }
SEL selector = NSSelectorFromString(@"someMethod");
IMP imp = [_controller methodForSelector:...
What are the most widely used C++ vector/matrix math/linear algebra libraries, and their cost and be
It seems that many projects slowly come upon a need to do matrix math, and fall into the trap of first building some vector classes and slowly adding in functionality until they get caught building a half-assed custom linear algebra library, and depending on it.
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Explicitly calling return in a function or not
... Urbanek from the R core team (I believe) for recommending a user to explicitly calling return at the end of a function (his comment was deleted though):
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Executing JavaScript without a browser?
I am looking into Javascript programming without a browser. I want to run scripts from the Linux or Mac OS X command line, much like we run any other scripting language (ruby, php, perl, python...)
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Are negative array indexes allowed in C?
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That is correct. From C99 §6.5.2.1/2:
The definition of the subscript
operator [] is that E1[E2] is
identical to (*((E1)+(E2))).
There's no magic. It's a 1-1 equivalence. As always when dereferencing a pointer (*), you need to be sure it's pointing to a valid addr...
What is move semantics?
...t finished listening to the Software Engineering radio podcast interview with Scott Meyers regarding C++0x . Most of the new features made sense to me, and I am actually excited about C++0x now, with the exception of one. I still don't get move semantics ... What is it exactly?
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How to use Elasticsearch with MongoDB?
I have gone through many blogs and sites about configuring Elasticsearch for MongoDB to index Collections in MongoDB but none of them were straightforward.
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Your project contains error(s), please fix it before running it
I am developing a simple Android application. But when I run Eclipse, it shows the following error:
26 Answers
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Should a retrieval method return 'null' or throw an exception when it can't produce the return value
...sing java language,I have a method that is supposed to return an object if it is found.
36 Answers
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Comparison of Android networking libraries: OkHTTP, Retrofit, and Volley [closed]
...can provide some concrete examples of best use cases for each.
Use Retrofit if you are communicating with a Web service. Use the peer library Picasso if you are downloading images. Use OkHTTP if you need to do HTTP operations that lie outside of Retrofit/Picasso.
Volley roughly competes with Retr...