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Why is require_once so bad to use?

...system keeps a log of what's already been included/required. Every *_once call means checking that log. So there's definitely some extra work being done there but enough to detriment the speed of the whole app? ... I really doubt it... Not unless you're on really old hardware or doing it a lot. I...
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Why prefer two's complement over sign-and-magnitude for signed numbers?

...o add them. Two's complement addition is very simple. You add numbers normally and any carry bit at the end is discarded. So they're added as follows: 0010 + 1111 =10001 = 0001 (discard the carry) 0001 is 1, which is the expected result of "2+(-1)". But in your "intuitive" method, adding is m...
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How can I time a code segment for testing performance with Pythons timeit?

...r if you want to average the time elapsed by several runs, you have to manually call the function multiple times (As I think you already do in you example code and timeit does automatically when you set its number argument) import time def myfast(): code n = 10000 t0 = time.time() for i in ran...
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What is the documents directory (NSDocumentDirectory)?

...ath = paths.firstObject; return basePath; } This Documents directory allows you to store files and subdirectories your app creates or may need. To access files in the Library directory of your apps sandbox use (in place of paths above): [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory...
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What is uint_fast32_t and why should it be used instead of the regular int and uint32_t?

... int may be as small as 16 bits on some platforms. It may not be sufficient for your application. uint32_t is not guaranteed to exist. It's an optional typedef that the implementation must provide iff it has an unsigned integer type of exactl...
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What does a type followed by _t (underscore-t) represent?

... As Douglas Mayle noted, it basically denotes a type name. Consequently, you would be ill-advised to end variable or function names with '_t' since it could cause some confusion. As well as size_t, the C89 standard defines wchar_t, off_t, ptrdiff_t, and p...
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In which case do you use the JPA @JoinTable annotation?

... project_id name name task_id The Project_Tasks table is called a "Join Table". To implement this second solution in JPA you need to use the @JoinTable annotation. For example, in order to implement a uni-directional one-to-many association, we can define our entities as such: Proj...
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Undefined reference to `pow' and `floor'

... Look in /lib or /usr/lib. The libraries are all named lib<name>.a or lib<name>.so - it's the "<name>" you put after the -l. In this case, the math library is named libm.so, so we call it -lm. – ams Dec 29 '11 at ...
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How to identify platform/compiler from preprocessor macros?

... I'm sorry, but this answer is quite incorrect on all accounts and doesn't even answer the question. – rubenvb Jan 27 '15 at 20:13 ...
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Can I use __init__.py to define global variables?

I want to define a constant that should be available in all of the submodules of a package. I've thought that the best place would be in in the __init__.py file of the root package. But I don't know how to do this. Suppose I have a few subpackages and each with several modules. How can I access th...