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How efficient is locking an unlocked mutex? What is the cost of a mutex?

...tefultask-testsuite/blob/b69b112e2e91d35b56a39f41809d3e3de2f9e4b8/src/mutex_test.cxx Note that it has a few hardcoded values specific for my box (xrange, yrange and rdtsc overhead), so you probably have to experiment with it before it will work for you. The graph it produces in that state is: T...
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Does C# have an equivalent to JavaScript's encodeURIComponent()?

...er my 4 hour experiments I found this c# CODE: string a = "!@#$%^&*()_+ some text here али мамедов баку"; a = System.Web.HttpUtility.UrlEncode(a); a = a.Replace("+", "%20"); the result is: !%40%23%24%25%5e%26*()_%2b%20some%20text%20here%20%d0%b0%d0%bb%d0%b8%20%d0%bc%d0%b0%d0%bc...
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Is there a Mutex in Java?

...ock; import java.util.concurrent.locks.ReentrantLock; private final Lock _mutex = new ReentrantLock(true); _mutex.lock(); // your protected code here _mutex.unlock(); share | improve this answ...
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How to get first element in a list of tuples?

... do you mean something like this? new_list = [ seq[0] for seq in yourlist ] What you actually have is a list of tuple objects, not a list of sets (as your original question implied). If it is actually a list of sets, then there is no first element because set...
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Position of least significant bit that is set

... 7, 26, 12, 18, 6, 11, 5, 10, 9 }; r = MultiplyDeBruijnBitPosition[((uint32_t)((v & -v) * 0x077CB531U)) >> 27]; Helpful references: "Using de Bruijn Sequences to Index a 1 in a Computer Word" - Explanation about why the above code works. "Board Representation > Bitboards > BitSca...
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How do I append one string to another in Python?

...O(n^2), but now it is O(n). From the source (bytesobject.c): void PyBytes_ConcatAndDel(register PyObject **pv, register PyObject *w) { PyBytes_Concat(pv, w); Py_XDECREF(w); } /* The following function breaks the notion that strings are immutable: it changes the size of a string. We g...
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How to set a Django model field's default value to a function call / callable (e.g., a date relative

..., timedelta class MyModel(models.Model): # default to 1 day from now my_date = models.DateTimeField(default=datetime.now() + timedelta(days=1)) This last line is not defining a function; it is invoking a function to create a field in the class. PRE Django 1.7 Django lets you pass a callable...
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Spring Data JPA find by embedded object property

...Long twoId); and results in a query of the form: select ...... from one one_ left outer join two two_ on one_.two_id = two_.id where one_id = ? and two_.id = ? – TroJaN May 4 at 17:17 ...
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Refresh a page using JavaScript or HTML [duplicate]

...g (ajax) at loading. for example: www.yoursite.com/page/about?getVer=1&__[date] Compare it to the stored versionnumber (stored in cookie or localStorage) if user has visited the page once, otherwise store it directly. If version is not the same as local version, refresh the page using window.loc...
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How do I move files in node.js?

...e rename function to do that. http://nodejs.org/docs/latest/api/fs.html#fs_fs_rename_oldpath_newpath_callback fs.rename(oldPath, newPath, callback) Added in: v0.0.2 oldPath <String> | <Buffer> newPath <String> | <Buffer> callback <Function> Asynchronous...