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Lock, mutex, semaphore… what's the difference?
... that's locked and the lock is not shared with any other processes.
A mutex is the same as a lock but it can be system wide (shared by multiple processes).
A semaphore does the same as a mutex but allows x number of threads to enter, this can be used for example to limit the number of cpu, io or r...
std::vector performance regression when enabling C++11
... # 0.986 CPUs utilized ( +- 1.75% )
4 context-switches # 0.116 K/sec ( +- 5.69% )
0 CPU-migrations # 0.006 K/sec ( +- 66.67% )
19,801 page-faults # 0.559 M/s...
STL or Qt containers?
...
I started by using std::(w)string and the STL containers exclusively and converting to/from the Qt equivalents, but I have already switched to QString and I find that I'm using Qt's containers more and more.
When it comes to strings, QString offers much more complete functionality ...
In Firebase, is there a way to get the number of children of a node without loading all the node dat
... this code tracking upvodes:
var upvotesRef = new Firebase('https://docs-examples.firebaseio.com/android/saving-data/fireblog/posts/-JRHTHaIs-jNPLXOQivY/upvotes');
upvotesRef.transaction(function (current_value) {
return (current_value || 0) + 1;
});
For more info, see https://www.firebase.com/...
How to get UTF-8 working in Java webapps?
...s + JSP, no framework used) to support äöå etc. for regular Finnish text and Cyrillic alphabets like ЦжФ for special cases.
...
What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
..., the performance hit can be very significant.
– tucuxi
Aug 30 '10 at 10:43
218
@tucuxi I'm surpr...
Is recursion ever faster than looping?
...he language being used. You wrote 'language-agnostic', so I'll give some examples.
In Java, C, and Python, recursion is fairly expensive compared to iteration (in general) because it requires the allocation of a new stack frame. In some C compilers, one can use a compiler flag to eliminate this o...
List of Delphi language features and version in which they were introduced/deprecated
...e to point out that I have honestly and genuinely searched repeatedly and exhaustively via Google for such a thing, and been unable to find one.
...
How do cache lines work?
...d a store-reload has a store-forwarding latency of 4 or 5 cycles on modern x86 CPUs. Things are similar on other architectures.
Further reading: Ulrich Drepper's What Every Programmer Should Know About Memory. The software-prefetch advice is a bit outdated: modern HW prefetchers are smarter, and ...