PHP uses the debug_backtrace method to track code calls

During the development process, for example, if you want to modify the code developed by others or debug the problematic code, you need to track the code process step by step, find the problematic areas, and make modifications. If there is a method that can get which method a certain piece of code is called, and can go back to the place where it was first called (including the file called, the number of lines, parameters, etc.), it will be easy to locate the problem. place.

php's debug_backtrace method can trace code calls to facilitate debugging the code.

debug_backtrace method description

Generate a backtrace (backtrace)

array debug_backtrace ([ int $options = DEBUG_BACKTRACE_PROVIDE_OBJECT [, int $limit = 0 ]] )

Parameters

options

DEBUG_BACKTRACE_PROVIDE_OBJECT
Whether to fill the index of "object".

DEBUG_BACKTRACE_IGNORE_ARGS
Whether to ignore the index of "args", including all function/method parameters, can save memory overhead.

limit
This parameter can be used to limit the number of stack frames returned. The default is (limit=0), and all stack frames are returned.


Return value

Returns an array containing many associative arrays. Possible returned elements:

名字         类型    说明function    string  当前的函数名，参见： __FUNCTION__。
line        integer 当前的行号。参见： __LINE__。
file        string  当前的文件名。参见： __FILE__。class       string  当前 class 的名称。参见 __CLASS__object      object  当前的 object。
type        string  当前调用的类型。如果是一个方法，会返回 "->"。如果是一个静态方法，会返回 "::"。 如果是一个函数调用，则返回空。
args        array   如果在一个函数里，这会列出函数的参数。 如果是在一个被包含的文件里，会列出包含的文件名。

Example

Get the user information and user information of the order. The calling process is index->order->user->message, and finally returns the sorted information.

Suppose we find that the data of the message is incorrect during debugging, we can use the debug_backtrace method on the message to view the calling process and parameters, and check which step has the problem.

Use DEBUG_BACKTRACE_IGNORE_ARGS will ignore args (parameters of method call)

index.php

get_order($order_id);?>

order.php

get_user($user_id);        // 订单资料
        $order_info = array(            'order_id' => $order_id,            'order_name' => 'my order',            'user_info' => $user_info,
        );        return $order_info;
    }
}?>

user.php

get_message($user_id);        $user_info = array(                'user_id' => $user_id,                'name' => 'fdipzone',                'message' => $user_message
        );        return $user_info;
    }
}?>

message.php

1, 'title'=>'message1'),            array('id'=>2, 'title'=>'message2'),
        );        // 加入跟踪调试
        $backtrace = debug_backtrace();
        var_dump($backtrace);        return $message;
    }
}?>

Run index.php, output

/message.php:15:array (size=3)  0 => 
    array (size=7)      'file' => string '/user.php' (length=9)      'line' => int 12
      'function' => string 'get_message' (length=11)      'class' => string 'Message' (length=7)      'object' => 
        object(Message)[3]      'type' => string '->' (length=2)      'args' => 
        array (size=1)          0 => int 1001
  1 => 
    array (size=7)      'file' => string '/order.php' (length=10)      'line' => int 14
      'function' => string 'get_user' (length=8)      'class' => string 'User' (length=4)      'object' => 
        object(User)[2]      'type' => string '->' (length=2)      'args' => 
        array (size=1)          0 => int 1001
  2 => 
    array (size=7)      'file' => string '/index.php' (length=9)      'line' => int 8
      'function' => string 'get_order' (length=9)      'class' => string 'Order' (length=5)      'object' => 
        object(Order)[1]      'type' => string '->' (length=2)      'args' => 
        array (size=1)          0 => int 1000000

You can see that the calling process is

1.index.php
line 8
class Order
function get_order
args int 1000000

2.order.php
line 14
class User
function get_user
args int 1001

3.user.php
line 12
class Message
function get_message
args int 1001

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