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How efficient is locking an unlocked mutex? What is the cost of a mutex?
... access to the object happens often, then multiple locks would increase parallelism. At the cost of maintainability, since more locking means more debugging of the locking.
How efficient is it to lock a mutex? I.e. how much assembler instructions are there likely and how much time do they take (...
Is C++ context-free or context-sensitive?
... is (probably) Turing-complete, since it shows a program which is syntactically correct if and only if a given integer is prime.
So I assert that C++ is neither context-free nor context-sensitive.
If you allow arbitrary symbol sequences on both sides of any production, you produce an Type-0 gramma...
Accessing Object Memory Address
When you call the object.__repr__() method in Python you get something like this back:
9 Answers
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Read whole ASCII file into C++ std::string [duplicate]
...pdate: Turns out that this method, while following STL idioms well, is actually surprisingly inefficient! Don't do this with large files. (See: http://insanecoding.blogspot.com/2011/11/how-to-read-in-file-in-c.html)
You can make a streambuf iterator out of the file and initialize the string with it...
Clear Text Selection with JavaScript
... window.getSelection().empty();
} else if (window.getSelection().removeAllRanges) { // Firefox
window.getSelection().removeAllRanges();
}
} else if (document.selection) { // IE?
document.selection.empty();
}
Credit to Mr. Y.
...
Difference between Django's annotate and aggregate methods?
...rage_price': 34.35}
Returns a dictionary containing the average price of all books in the queryset.
Annotation
>>> q = Book.objects.annotate(num_authors=Count('authors'))
>>> q[0].num_authors
2
>>> q[1].num_authors
1
q is the queryset of books, but each book has been...
Warning message: In `…` : invalid factor level, NA generated
...
Here is a flexible approach, it can be used in all cases, in particular:
to affect only one column, or
the dataframe has been obtained from applying previous operations (e.g. not immediately opening a file, or creating a new data frame).
First, un-factorize a stri...
What's the difference between “git reset” and “git checkout”?
...
git reset is specifically about updating the index, moving the HEAD.
git checkout is about updating the working tree (to the index or the specified tree). It will update the HEAD only if you checkout a branch (if not, you end up with a detached H...
Calling a function when ng-repeat has finished
What I am trying to implement is basically a "on ng repeat finished rendering" handler. I am able to detect when it is done but I can't figure out how to trigger a function from it.
...
Fluent Validation vs. Data Annotations [closed]
...when used for ASP.NET MVC validatation? They seem to have similar objects, all the way to their object names. Is one related to another? What are their differences? In what way do these differences denote different use cases?
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