获取函数被调用的行？

Question

我看了这个,我知道答案可能涉及使用debug_backtrace(),但我正在努力如何使用它或它究竟是做什么.

基本上,如果这是index.php:

<?php
//some code
//some more code

require "functions.php";

print_line();

//some code

print_line();
?>

和functions.php是:

<?php
function print_line(){
    $line="[line that this function was called at]";
    print "This function was called from line $line of index.php<br />";
}
?>

设置的正确方法是什么,$line以便输出为:

This function was called from line 7 of index.php
This function was called from line 11 of index.php

Answer 1

debug_backtrace()包含所有嵌套函数调用,一直到当前作用域的索引从0开始(最接近).

所以当你需要调用print_line()的行时,只需要:

<?php
function print_line(){
    $backtrace = debug_backtrace();

    $line=$backtrace[0]['line'];
    print "This function was called from line $line of index.php<br />";
}

或者从PHP 5.4开始:

$line=debug_backtrace()[0]['line'];