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Message Queue vs Message Bus — what are the differences?
And are there any? To me, MB knows both subscribers and publishers and acts as a mediator, notifying subscribers on new messages (effectively a "push" model). MQ, on the other hand, is more of a "pull" model, where consumers pull messages off a queue.
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Checking if a double (or float) is NaN in C++
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According to the IEEE standard, NaN values have the odd property that comparisons involving them are always false. That is, for a float f, f != f will be true only if f is NaN.
Note that, as some comments below have pointed out, not all compilers ...
What is move semantics?
...cott 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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Getting output of system() calls in Ruby
If I call a command using Kernel#system in Ruby, how do I get its output?
15 Answers
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Function overloading by return type?
...Contrary to what others are saying, overloading by return type is possible and is done by some modern languages. The usual objection is that in code like
int func();
string func();
int main() { func(); }
you can't tell which func() is being called. This can be resolved in a few ways:
Have a p...
Saving and loading objects and using pickle
I´m trying to save and load objects using pickle module.
First I declare my objects:
7 Answers
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Difference between InvariantCulture and Ordinal string comparison
...trings in c# for equality, what is the difference between InvariantCulture and Ordinal comparison?
9 Answers
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How to UPSERT (MERGE, INSERT … ON DUPLICATE UPDATE) in PostgreSQL?
...o do an upsert, which is what MySQL calls INSERT ... ON DUPLICATE UPDATE and the standard supports as part of the MERGE operation.
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How do I select elements of an array given condition?
...e elements in y corresponding to elements in x that are greater than 1 and less than 5.
6 Answers
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Can not connect to local PostgreSQL
...really looks like a file permissions error. Unix domain sockets are files and have user permissions just like any other. It looks as though the OSX user attempting to access the database does not have file permissions to access the socket file. To confirm this I've done some tests on Ubuntu and p...