PHP debug_backtrace() Function

The PHP debug_backtrace() function is used to generates a PHP backtrace.

Syntax

debug_backtrace(options, limit)

Parameters

`options`	`Optional.` Specify this parameter as a bitmask for the following options: DEBUG_BACKTRACE_PROVIDE_OBJECT - (default) 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.
`limit`	`Optional.` This parameter can be used to limit the number of stack frames returned. By default (limit=0) it returns all stack frames.

Return Value

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

Name	Type	Description
function	string	The current function name.
line	int	The current line number.
file	string	The current file name.
class	string	The current class name.
object	object	The current object.
type	string	The current call type. Possible calls: 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, it lists the functions arguments. If inside an included file, it lists the included file names.

Example: debug_backtrace() example

The example below shows the usage of debug_backtrace() function.

<?php
function test_a($x, $y){
  echo "\$x + \$y = ".($x + $y)."\n";
  var_dump(debug_backtrace());
}

test_a(10, 20);
?>

The output of the above code will be:

$x + $y = 30
array(1) {
  [0]=>
  array(4) {
    ["file"]=>
    string(39) "Main.php"
    ["line"]=>
    int(7)
    ["function"]=>
    string(6) "test_a"
    ["args"]=>
    array(2) {
      [0]=>
      int(10)
      [1]=>
      int(20)
    }
  }
}

Example: debug_backtrace() example

Consider one more example on debug_backtrace() function.

<?php
function test_a($str){
  test_b($str);
}

function test_b($str){
  echo "Hi $str \n";
  var_dump(debug_backtrace());
}

test_a('friend');
?>

The output of the above code will be:

Hi friend 
array(2) {
  [0]=>
  array(4) {
    ["file"]=>
    string(39) "Main.php"
    ["line"]=>
    int(3)
    ["function"]=>
    string(6) "test_b"
    ["args"]=>
    array(1) {
      [0]=>
      string(6) "friend"
    }
  }
  [1]=>
  array(4) {
    ["file"]=>
    string(39) "Main.php"
    ["line"]=>
    int(11)
    ["function"]=>
    string(6) "test_a"
    ["args"]=>
    array(1) {
      [0]=>
      string(6) "friend"
    }
  }
}

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