debug_backtrace

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

debug_backtrace — Generates a backtrace

Description

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

debug_backtrace() generates a PHP backtrace.

Parameters

options

This parameter is a bitmask for the following options:

debug_backtrace() options
DEBUG_BACKTRACE_PROVIDE_OBJECT Whether or not to populate the "object" index.
DEBUG_BACKTRACE_IGNORE_ARGS Whether or not to omit the "args" index, and thus all the function/method arguments, to save memory.

Note:

There are four possible combinations:

debug_backtrace() options
debug_backtrace() Populates both indexes
debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT)
debug_backtrace(1)
debug_backtrace(0) Omits index "object" and populates index "args".
debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS) Omits index "object" and index "args".
debug_backtrace(2)
debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT|DEBUG_BACKTRACE_IGNORE_ARGS) Populate index "object" and omit index "args".
debug_backtrace(3)

limit

This parameter can be used to limit the number of stack frames returned. By default (limit=0) it returns all stack frames.

Return Values

Returns an array of associative arrays. The possible returned elements are as follows:

Possible returned elements from debug_backtrace()
Name Type Description
function string The current function name. See also __FUNCTION__.
line int The current line number. See also __LINE__.
file string The current file name. See also __FILE__.
class string The current class name. See also __CLASS__
object object The current object.
type string The current call type. If a method call, "->" is returned. If a static method call, "::" is returned. If a function call, nothing is returned.
args array If inside a function, this lists the functions arguments. If inside an included file, this lists the included file name(s).

Examples

Example #1 debug_backtrace() example

<?php
// filename: /tmp/a.php

function a_test($str)
{
echo "\nHi: $str";
var_dump(debug_backtrace());
}

a_test('friend');
?>

<?php
// filename: /tmp/b.php
include_once '/tmp/a.php';
?>

Results similar to the following when executing /tmp/b.php: 

Hi: friend
array(2) {
[0]=>
array(4) {
    ["file"] => string(10) "/tmp/a.php"
    ["line"] => int(10)
    ["function"] => string(6) "a_test"
    ["args"]=>
    array(1) {
      [0] => &string(6) "friend"
    }
}
[1]=>
array(4) {
    ["file"] => string(10) "/tmp/b.php"
    ["line"] => int(2)
    ["args"] =>
    array(1) {
      [0] => string(10) "/tmp/a.php"
    }
    ["function"] => string(12) "include_once"
  }
}

See Also