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Why can't C compilers rearrange struct members to eliminate alignment padding? [duplicate]
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There are multiple reasons why the C compiler cannot automatically reorder the fields:
The C compiler doesn't know whether the struct represents the memory structure of objects beyond the current compilation unit (for example: a foreign library, a file on disc, network data, CPU page ...
How to include external Python code to use in other files?
...ods in a file, is there a way to include those files in another file, but call them without any prefix (i.e. file prefix)?
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How do I write a short literal in C++?
...rt enough to compile this as if it's a short literal (i.e. it wouldn't actually allocate an int and then cast it every time).
The following illustrates how much you should worry about this:
a = 2L;
b = 2.0;
c = (short)2;
d = '\2';
Compile -> disassemble ->
movl $2, _a
movl $2, _b
m...
Get class name of django model
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Django models are derived from the ModelBase, which is the Metaclass for all models.
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Is it possible to declare two variables of different types in a for loop?
...and clang for years (since gcc-7 and clang-4.0) (clang live example). This allows us to unpack a tuple like so:
for (auto [i, f, s] = std::tuple{1, 1.0, std::string{"ab"}}; i < N; ++i, f += 1.5) {
// ...
}
The above will give you:
int i set to 1
double f set to 1.0
std::string s set to "...
Why is parenthesis in print voluntary in Python 2.7?
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In Python 2.x print is actually a special statement and not a function*.
This is also why it can't be used like: lambda x: print x
Note that (expr) does not create a Tuple (it results in expr), but , does. This likely results in the confusion between...
Why would one use nested classes in C++?
... it at any time so you can not use it.
Look at std::list or std::map they all contain hidden classes (or do they?). The point is they may or may not, but because the implementation is private and hidden the builders of the STL were able to update the code without affecting how you used the code, or...
Chrome Extension how to send data from content script to popup.html
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Although you are definitely in the right direction (and actually pretty close to the end), there are several (imo) bad practises in your code (e.g. injecting a whole library (jquery) for such a trivial task, declaring unnecessary permissions, making superflous calls to API methods etc...
Why does GCC generate 15-20% faster code if I optimize for size instead of speed?
... gcc-4.8 1.53s 1.52s -Os
In some cases you can alleviate the effect of disadvantageous optimizations by asking gcc to optimize for your particular processor (using options -mtune=native or -march=native):
Processor Compiler Time (-O2 -mtune=native) Time (-Os...
How can I create directory tree in C++/Linux?
...C++ compilers.
/*
@(#)File: mkpath.c
@(#)Purpose: Create all directories in path
@(#)Author: J Leffler
@(#)Copyright: (C) JLSS 1990-2020
@(#)Derivation: mkpath.c 1.16 2020/06/19 15:08:10
*/
/*TABSTOP=4*/
#include "posixver.h"
#include "mkpath.h"
#include "emalloc...