Usted buscó: callbacks (Coreano - Inglés)

php는 가변 함수(variable functions) 개념을 지원한다. 이것은 변수명 뒤에 괄호가 왔을 때, php는 그 이름을 가진 함수를 찾아 실행한다는 것을 의미한다. 이 기능은 callbacks, function table 등의 기능에 사용하면 매우 유용하게 사용할 수 있다
among other things, this can be used to implement callbacks, function tables, and so forth.

pcntl now uses ticks as the signal handle callback mechanism, which is much faster than the previous mechanism. this change follows the same semantics as using "user ticks". you use the declare() statement to specify the locations in your program where callbacks are allowed to occur. this allows you to minimize the overhead of handling asynchronous events. in the past, compiling php with pcntl enabled would always incur this overhead, whether or not your script actually used pcntl.
this allows you to minimize the overhead of handling asynchronous events.