Search results
Results from the WOW.Com Content Network
In computer programming, a callback is a function that is stored as data (a reference) and designed to be called by another function – often back to the original abstraction layer. A function that accepts a callback parameter may be designed to call back before returning to its caller which is known as synchronous or blocking .
A typical use of a function object is in writing callback functions. A callback in procedural languages, such as C, may be performed by using function pointers. [2] However it can be difficult or awkward to pass a state into or out of the callback function. This restriction also inhibits more dynamic behavior of the function.
Each deferred supports a callback chain. When the deferred gets the value, it is passed to the functions on the callback chain, with the result of each callback becoming the input for the next. Deferreds make it possible to operate on the result of a function call before its value has become available.
A function written in continuation-passing style takes an extra argument: an explicit "continuation"; i.e., a function of one argument. When the CPS function has computed its result value, it "returns" it by calling the continuation function with this value as the argument.
In an event-driven application, there is generally an event loop that listens for events and then triggers a callback function when one of those events is detected. Event-driven programs can be written in any programming language , although the task is easier in languages that provide high-level abstractions .
Webhooks are "user-defined HTTP callbacks". [2] They are usually triggered by some event, such as pushing code to a repository, [3] a new comment or a purchase, [4] a comment being posted to a blog [5] and many more use cases. [6] When that event occurs, the source site makes an HTTP request to the URL configured for the webhook.
Also, it has FFIs via JavaScript callback functions for access to methods and properties of mobile phone's native features including accelerometer, camera (also PhotoLibrary and SavedPhotoAlbum), compass, storage (SQL database and localStorage), notification, media and capture (playing and recording or audio and video), file, contacts (address ...
rcviz : Python module for rendering runtime-generated call graphs with Graphviz. Each node represents an invocation of a function with the parameters passed to it and the return value. XQuery. XQuery Call Graphs from the XQuery Wikibook: A call graph generator for an XQuery function module that uses Graphviz