C Interrupt Service Routine (ISR) Declaration: int_t1() interrupt 3

This\ is\ a\ function\ declaration\ in\ C\ that\ specifies\ that\ the\ function\ "int_t1"\ is\ an\ interrupt\ service\ routine\ (ISR)\ for\ interrupt\ 3.\ \n\nIn\ C,\ interrupts\ are\ used\ to\ handle\ asynchronous\ events\ that\ occur\ during\ program\ execution.\ When\ an\ interrupt\ occurs,\ the\ CPU\ suspends\ the\ current\ program\ execution\ and\ transfers\ control\ to\ the\ corresponding\ ISR\ to\ handle\ the\ interrupt.\ \n\nThe\ "void"\ keyword\ indicates\ that\ the\ ISR\ does\ not\ return\ a\ value.\ The\ "interrupt"\ keyword\ is\ used\ to\ specify\ that\ it\ is\ an\ ISR.\ The\ "3"\ after\ the\ "interrupt"\ keyword\ specifies\ the\ interrupt\ number,\ which\ determines\ which\ hardware\ or\ software\ event\ triggers\ the\ ISR.