x
Home / 🔮 world building / science and engineering / Mathematics / computer science / Development / general programming / Callbacks

Callbacks

Callbacks or callback functions are references that are passed as arguments to a piece of code, which will execute whenever an event associated with the callback function occurs.

The function will be executed externally by an API.

Generally it is used to call a higher level subroutine from a lower-level software like the operating system.

Examples

  • Windows API - e.g. WaveOutProc()
  • In JavaScript, they are functions passed as arguments to other functions, for calling other functions from a function
  • A pseudocode example: 
  funct printANumber(int n, callback callbackFunction) {
      printout("Printing" + n);
  }
  funct printFinishMessage(){
      printout("Finished printing.");
  }
  funct main() {
      printANumber(6, printFinishMessage);
  }

The output will be: 

  Printing 6
  Finished printing
Left-click: follow link, Right-click: select node, Scroll: zoom
x