In his book The C++ Standard Library (Second Edition) Nicolai Josuttis states that lambdas can be better optimized by the compiler than plain functions. In addition, C++ compilers optimize lambdas better than they do ordinary functions. (Page 213) Why is that? I thought when it comes to inlining there shouldn’t be any difference any more. … Read more
Is there a reliable cross-browser way to detect that a tab has focus. The scenario is that we have an application that polls regularly for stock prices, and if the page doesn’t have focus we could stop the polling and save everyone the traffic noise, especially as people are fans of opening several tabs with … Read more
GHC has a lot of optimizations that it can perform, but I don’t know what they all are, nor how likely they are to be performed and under what circumstances. My question is: what transformations can I expect it to apply every time, or nearly so? If I look at a piece of code that’s … Read more
Specifically, if I have a series of if…else if statements, and I somehow know beforehand the relative probability that each statement will evaluate to true, how much difference in execution time does it make to sort them in order of probability? For example, should I prefer this: if (highly_likely) //do something else if (somewhat_likely) //do … Read more
Does creating an object using reflection rather than calling the class constructor result in any significant performance differences? 14 Answers 14
Is it better to use memcpy as shown below or is it better to use std::copy() in terms to performance? Why? char *bits = NULL; … bits = new (std::nothrow) char[((int *) copyMe->bits)[0]]; if (bits == NULL) { cout << “ERROR Not enough memory.\n”; exit(1); } memcpy (bits, copyMe->bits, ((int *) copyMe->bits)[0]); 8 Answers 8
This is a follow-up question to an answer I gave a few days back. Edit: it seems that the OP of that question already used the code I posted to him to ask the same question, but I was unaware of it. Apologies. The answers provided are different though! Substantially I observed that: >>> def … Read more
Below two methods did not help me. My jQuery is always on the head section. What can be the reason? Method 1: (adding below code to function.php) if (!is_admin()) add_action(“wp_enqueue_scripts”, “my_jquery_enqueue”, 11); function my_jquery_enqueue() { wp_deregister_script(‘jquery’); wp_enqueue_script( ‘jquery’, ‘https://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js’,array(),’1.9.0′,true); } this one works when I change ‘jquery’, to some other string as first parameter in … Read more
I’m asking this just for the sake of shaving a few bytes. I know I can use +x (unary plus) instead of Number(x). Is there a difference between those and parseFloat? 5 Answers 5
I want to find out how much time a certain function takes in my C++ program to execute on Linux. Afterwards, I want to make a speed comparison . I saw several time function but ended up with this from boost. Chrono: process_user_cpu_clock, captures user-CPU time spent by the current process Now, I am not … Read more