How to print call stack in PHP

In the given PHP code, the child_func() function calls the parent_func() function, which further calls the grandparent_func() function, thus generating a call stack.

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The three methods of PHP printing call stack are as follows:

Method 1: Use the debug_print_backtrace() function to print the call stack.

Example:

<?php 
// 用于打印PHP调用堆栈的PHP程序
//调用函数parent_func
function child_func() { 
    parent_func(); 
} 
  
// 调用grandparent_func函数
function parent_func() { 
    grandparent_func(); 
} 
  
// 函数的作用是:打印调用堆栈
function grandparent_func() { 
    debug_print_backtrace(); 
} 
  
//主函数调用 
child_func(); 
  
?>

Output:

#0  grandparent_func() called at [/home/905a3b4d90f10b30521fedcb56c99fba.php:12]
#1  parent_func() called at [/home/905a3b4d90f10b30521fedcb56c99fba.php:7]
#2  child_func() called at [/home/905a3b4d90f10b30521fedcb56c99fba.php:21]

Method 2: Use the debug_backtrace() function to print the call stack.

Example:

<?php 
// 用于打印PHP调用堆栈的PHP程序
//函数调用parent_func
function child_func() { 
    parent_func(); 
} 
  
// 函数调用grandparent_func
function parent_func() { 
    grandparent_func(); 
} 
  
// 函数的作用是:打印调用堆栈
function grandparent_func() { 
    var_dump(debug_backtrace()); 
} 
  
// 主函数调用 
child_func(); 
  
?>

Output:

array(3) {
  [0]=>
  array(4) {
    ["file"]=>
    string(42) "/home/2b81f040639170c49a6a58adb23d5154.php"
    ["line"]=>
    int(12)
    ["function"]=>
    string(16) "grandparent_func"
    ["args"]=>
    array(0) {
    }
  }
  [1]=>
  array(4) {
    ["file"]=>
    string(42) "/home/2b81f040639170c49a6a58adb23d5154.php"
    ["line"]=>
    int(7)
    ["function"]=>
    string(11) "parent_func"
    ["args"]=>
    array(0) {
    }
  }
  [2]=>
  array(4) {
    ["file"]=>
    string(42) "/home/2b81f040639170c49a6a58adb23d5154.php"
    ["line"]=>
    int(21)
    ["function"]=>
    string(10) "child_func"
    ["args"]=>
    array(0) {
    }
  }
}

Method 3: The getTraceAsString() member function of the Exception class returns a call stack.

Example:

<?php 
// 用于打印PHP调用堆栈的PHP程序
//函数调用parent_func
function child_func() { 
    parent_func(); 
} 
  
// 函数调用grandparent_func
function parent_func() { 
    grandparent_func(); 
} 
  
// 函数的作用是:打印调用堆栈
function grandparent_func() { 
    $e = new Exception; 
    var_dump($e->getTraceAsString()); 
} 
  
// 主函数调用
child_func(); 
  
?>

Output:

string(207) "#0 /home/8d8303d43667a4915d43dab7d63de26d.php(12): grandparent_func()
#1 /home/8d8303d43667a4915d43dab7d63de26d.php(7): parent_func()
#2 /home/8d8303d43667a4915d43dab7d63de26d.php(22): child_func()
#3 {main}"

This article is an introduction to three methods on how to print the call stack in PHP. I hope it will be helpful to friends who need it. help!

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