Why is the onexit function not executed?

Writing a policy for statistics, ready to output the final statistical results with the onexit function, when retesting it found that the onexit function was not executed and the function name was changed to onExit. Please answer, thank you!

function onTick() { //do something here }

function onexit() { Log(“Exit now!!!”); }

function main() { for(var i=-30;i<31;i++) { g_s[i] = 0; }

while(true)
{
    onTick();
    
    Sleep(1000);
}

}