dispatch

问题 As Apple's document says, dispatch_get_global_queue() is a concurrent queue, and dispatch_sync is something meaning serial.Then the tasks are processed async or sync? 回答1: You're getting confused between what a queue is and what async vs sync means. A queue is an entity on which blocks can be run. These can be serial or concurrent. Serial means that if you put block on in the order A, B, C, D, then they will be executed A, then B, then C, then D. Concurrent means that these same blocks might

问题 I have a method which should support being called from any queue, and should expect to. It runs some code in a background thread itself, and then uses dispatch_get_main_queue when it returns a value to its block argument. I don't want it to force it onto the main queue if it wasn't when it entered the method. Is there a way to get a pointer to the current dispatch queue? 回答1: You do have the option of "dispatch_get_current_queue()", however the iOS 6.1 SDK defines this API with these

问题 I'm working my arse off trying to implement an alternative for vtables using enums and a ton of macro magic that's really starting to mess with my brain. I'm starting to think i'm not walking the right path since the code is getting uglier and uglier, and will not be fit for production by any means. How can the pattern of the following code be implemented with the least amount of redirection/operations? It has to be done in standard c++, up to 17. class A{ virtual void Update() = 0; // A is

问题 I'm having trouble understanding using D3 events and dispatch functions. I have a chart example that I've been working on called: "Vertical Bar Charts With Legends." Drawing the charts and the legends was easy enough but I'd like to add the ability to highlight each bar as I mouseover its correlating text legend, located to the right of the chart. I've read through all of the event documentation and even looked at a number of examples, most of which are pretty complicated, but I seem to be

问题 func getTopicIdFromMYSQL(){ let myUrl = NSURL(string: "xxxx") let request = NSMutableURLRequest(URL: myUrl!) request.HTTPMethod = "POST" let email:String = "xxx@gmail.com" let postString = "email=\(email)" request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding) let task = NSURLSession.sharedSession().dataTaskWithRequest(request){ data, response, error in if(error != nil){ print("Get all topic") print("error=\(error)") return } do { let json = try NSJSONSerialization

问题 I'm aware of the general ins and outs of the different OO systems in R and I'm all for staying in S3 whenever/as long as I can. However, the need for multiple dispatch keeps haunting me in professional projects and kept pulling me into S4 in the past. But I refuse to accept that I can't find a S3 emulation of multi dispatch à la S4 that is at least able to support my primary use case of avoiding unsystematic data drift: My analytical programs create data structures that I publish to

问题 I am new to ES6 and advanced javascript. I have seen examples of code using the axios http client like this: axios.xxx(...).then((res) => dispatch(success(res)) , (err)=> dispatch(error(err))) whereas I am doing: axios.xxx(...).then(function(res){...}).catch(function(err){...}); I tried to look up dispatch on MDN but only found DispatchEvent... which is not the same? I ask because although my code works, I am finding http error codes like 403 etc from my api are handled as errors by axios,

问题 I am developing with aurelia and using aurelia-store for app state management. On loading data from server, I want to change an isLoading field true/false to show mask on related components. So I have defined a property in my state isLoading (for example). In the loading action I want first change the loading state to true and after data retrieved to false. So that according to the value of this field (isLoading) I want to display the mask over component. I want something like this: export

问题 Using python3.4. Here I want use singledispatch to dispatch different type in __mul__ method . The code like this : class Vector(object): ## some code not paste @functools.singledispatch def __mul__(self, other): raise NotImplementedError("can't mul these type") @__mul__.register(int) @__mul__.register(object) # Becasue can't use Vector , I have to use object def _(self, other): result = Vector(len(self)) # start with vector of zeros for j in range(len(self)): result[j] = self[j]*other return

问题 for i in 0...attString.length-1 { attString.enumerateAttribute(NSBackgroundColorAttributeName, in: NSMakeRange(i,1), options: NSAttributedString.EnumerationOptions(rawValue: 0)) { (value, range, stop) -> Void in if let exValue = value as? UIColor { if self.compareColors(c1: exValue, c2: (UIColor(hex: 0x2e4270))) || self.compareColors(c1: exValue, c2: (UIColor(hex: 0xc0e1ff))) || self.compareColors(c1: exValue, c2: (UIColor(hex: 0x7a99b8))) || self.compareColors(c1: exValue, c2: (UIColor(hex: