<?php
function a($n) {
b($n,['x'=>'y']);
}
function b($n,$a) {
c($a,$n);
}
function c($a,$n){
// debug_print_backtrace();
// var_dump(json_encode(debug_backtrace()));
error_log(json_encode(debug_backtrace()), 3, '/tmp/backtrace.log');
}
a(1);