global

I'm currently developing a very fast algorithm, with one part of it being an extremely fast scanner and statistics function. In this quest, i'm after any performance benefit. Therefore, I'm also interested in keeping the code "multi-thread" friendly. Now for the question : i've noticed that putting some very frequently accessed variables and arrays into "Global", or "static local" (which does the same), there is a measurable performance benefit (in the range of +10%). I'm trying to understand why, and to find a solution about it, since i would prefer to avoid using these types of allocation.

So lets say I have a main.pl script and in that script I need to declare some variables (any kind of variable constant or normal) and those variables need to be available through all scripts and modules that I'll include from that main.pl script automatically. What I mean if I have a variable $myVar in main.pl and from main.pl I require script1.pl , script2.pl or script3.pm , and from anyone of those scripts I need to access $myVar as you would access any var defined in that specific script or module. I've searched on the net, but I've only found examples where you can access variables from

In C++, should we be prepending stuff in the global namespace with :: ? For example, when using WinAPI, which is in C, should I do ::HANDLE instead of HANDLE , and ::LoadLibrary instead of LoadLibrary ? What does C++ say about this? Is it generally a good idea, factoring in issues like readability and maintainability? As namespaces don't exists in C, don't use ::HANDLE to access HANDLE type. Using the prepending :: for global namespace is a good idea for readability, you know the type you want to access is from global namespace. Moreover, if you are in a nested namespace and declare your own

What would be the most appropriate way of sharing the database connection in the below snippet ( the db variable) with my routers/controllers without turning the db variable into a global? var mongo = require('mongoskin'), db = mongo.db(config.db.adress); app.use(function(req, res, next) { db.open(function(err, data) { (err) ? res.send('Internal server error', 500) : next(); }); }); // Setting up controllers here app.post('/users', require('./controllers/users').create); Coming from a PHP background, I came to think about Dependency Injection , but I have no idea if that's appropriate in node.

("variables" here refers to "names", I think, not completely sure about the definition pythonistas use) I have an object and some methods. These methods all need and all change the object's variables. How can I, in the most pythonic and in the best, respecting the techniques of OOP, way achieve to have the object variables used by the methods but also keep their original values for the other methods? Should I copy the object everytime a method is called? Should I save the original values and have a reset() method to reset them everytime a method needs them? Or is there an even better way? EDIT

I starting getting this error on my Angular app: The Angular Compiler requires TypeScript >=2.7.2 and <2.8.0 but 2.8.3 was found instead and when I try to downgrade typescript to the right version doing: npm install -g typescript@2.7.2 it says updated 1 package. when I verify typescript version using npm view typescript version I still get 2.8.3 I even tried removing typescript entirely using npm uninstall -g typescript but when I verify typescript version again npm view typescript version I still get 2.8.3 What are the commands to properly purge and restore typescript to a previous version

I'm using a set of Constant.m files, one per target, to define specific things for each target. For example: // Constants.h extern NSString * const kDatabaseFileName; //Constants.m NSString * const kDatabaseFileName = @"target_one.sqlite"; I'd also like to define an NSArray for each of my targets: NSArray * const kLabelNames = [[NSArray alloc] initWithObjects: @"nameLabel", @"addressLabel", nil]; But this gives "error: initializer element is not constant". Using 'arrayWithObjects` doesn't work either. Is this because the strings in my array are not constants? How can I set up an array as a