Node 0.8 introduces a new concept called “Domains”. They are very roughly analogousness to AppDomains in .net and provide a way of encapsulating a group of IO operations. They basically allow you to wrap your request processing calls in a context specific group. If this group throws any uncaught exceptions then they can be handled … Read more
If you want to specify a class method as a callback, you need to specify the object it belongs to: array_walk($fieldsArray, array($this, ‘test_print’)); From the manual: A method of an instantiated object is passed as an array containing an object at index 0 and the method name at index 1.
$.getJSON is asynchronous. That is, the code after the call is executed while $.getJSON fetches and parses the data and calls your callback. So, given this: a(); $.getJSON(“url”, function() { b(); }); c(); The order of the calls of a, b, and c may be either a b c (what you want, in this case) … Read more
To make your loop non-blocking, you must break it into sections and allow the JS event processing loop to consume user events before carrying on to the next section. The easiest way to achieve this is to do a certain amount of work, and then use setTimeout(…, 0) to queue the next chunk of work. … Read more
For Firefox it seems that PERMISSION_DENIED is raised only if “Never share” is selected; if the dialog is dismissed or “Not now” is selected, effectively nothing happens – even on mozillas geolocation demo if you dismiss the permissions UI nothing happens. This means that getCurrentPosition can return either because the user closed the confirmation UI, … Read more
I think this question deserves an update. I know the original question was for PHP version 5.2, but I came here looking for a solution and found one for newer versions of PHP and thought this might be useful for other people as well. For PHP 5.3 and up, you can use the ‘use‘ keyword … Read more
The terminology here is a bit fuzzy. In general the two attempt to achieve similar results. In general, a callback is a function (or delegate) that you register with the API to be called at the appropriate time in the flow of processing (e.g to notify you that the processing is at a certain stage) … Read more
Very simply, a callback needn’t be asynchronous. http://docs.apigee.com/api-baas/asynchronous-vs-synchronous-calls Synchronous: If an API call is synchronous, it means that code execution will block (or wait) for the API call to return before continuing. This means that until a response is returned by the API, your application will not execute any further, which could be perceived by … Read more
function ChangeDasPanel(controllerPath, postParams, f) { $.get( controllerPath, postParams, function(returnValue) { var $DasSpace = $(‘#DasSpace’); $DasSpace.hide( “slide”, { direction: “right” }, 1000, function() { $DasSpace.contents().remove(); $DasSpace.append(returnValue).css(“display”, “block”); $DasSpace.show(“slide”, { direction: “right” }, 1000); } ); if (typeof f == “function”) f(); else alert(‘meh’); } ); }; You can pass functions like any other object in JavaScript. … Read more
Rob’s answer is correct, though I’d like to share an example of a simple working callback / completion handler, you can download an example project below and experiment with the getBoolValue‘s input. Swift 5: func getBoolValue(number : Int, completion: (Bool)->()) { if number > 5 { completion(true) } else { completion(false) } } getBoolValue(number: 2) … Read more