programming languages - What does this explanation of callback mean? -

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i saw sentence programming language pragmatics, scott

the programmer wants handler—a special subroutine—to invoked when given event occurs. handlers known callback functions, because run-time system calls main program instead of being called it.

i don't quite understand explanation of reason of event handlers named "callback".

what 2 cases mean:

  • "the run-time system calls main program"
  • "being called it", i.e. run-time system called main program?

thanks.





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