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STL or Qt containers?
...r types, making std::copy() much less often needed.
STL containers have an Allocator template argument, making custom memory management trivial (typedef required), compared with Qt (fork of QLineEdit required for s/QString/secqstring/). EDIT 20171220: This cuts Qt off of advances in allocator design...
String concatenation: concat() vs “+” operator
...then throwing it away when you create the final String. In practice memory allocation is surprisingly fast.
Update: As Pawel Adamski notes, performance has changed in more recent HotSpot. javac still produces exactly the same code, but the bytecode compiler cheats. Simple testing entirely fails bec...
When should I use std::thread::detach?
...'s a situation when using detach would be a less evil alternative to, say, allocating thread object with dynamic storage duration and then purposely leaking it.
#include <LegacyApi.hpp>
#include <thread>
auto LegacyApiThreadEntry(void)
{
auto result{NastyBlockingFunction()};
//...
Determine the number of lines within a text file
...ne loads the entire contents of the file into an array which means it must allocate at least as much memory as the size of the file. The second merely loops one line at a time so it never has to allocate more than one line's worth of memory at a time. This isn't that important for small files, but f...
Explain the concept of a stack frame in a nutshell
...rocessor knows anything about stack, because WE manipulate it via subbing (allocation), pushing and popping. And so here are calling conventions which explain how we should use the stack.
– Victor Polevoy
Apr 18 '18 at 7:18
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In c++ what does a tilde “~” before a function name signify?
...tc.
Here's a description from ibm.com:
Destructors are usually used to deallocate memory and do other cleanup for a class object and its class members when the object is destroyed. A destructor is called for a class object when that object passes out of scope or is explicitly deleted.
See https:/...
What do the plus and minus signs mean in Objective-C next to a method?
...se?
[CustomClass classMethod];
CustomClass *classObject = [[CustomClass alloc] init];
[classObject instanceMethod];
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Why was “Avoid Enums Where You Only Need Ints” removed from Android's performance tips?
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TLDR: Dalvik was not good with memory allocation and Enum uses more memory than int. Android Lollipop replaced Dalvik with ART which does not suffer from the same limitations. Thus this recommendation is not relevant anymore.
The long answer:
Wow! 8 years, 5 a...
Objective-C categories in static library
...aining a class name, request a class pointer for that name and dynamically allocate the class. E.g. instead of
MyCoolClass * mcc = [[MyCoolClass alloc] init];
I could also write
NSString * cname = @"CoolClass";
NSString * cnameFull = [NSString stringWithFormat:@"My%@", cname];
Class mmcClass = N...
How do I append one string to another in Python?
...ugh memory to resize the string, the original
string object at *pv is deallocated, *pv is set to NULL, an "out of
memory" exception is set, and -1 is returned. Else (on success) 0 is
returned, and the value in *pv may or may not be the same as on input.
As always, an extra byte is alloc...