debug_backtrace

Description
Syntax
Examples
Links

Description

The debug_backtrace of Error Handling for PHP generates a backtrace.

Syntax

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

Parameters

options

A bitmask for the following options:

Number	Constant	Description
1	DEBUG_BACKTRACE_PROVIDE_OBJECT	Whether or not to populate the "object" index.
2	DEBUG_BACKTRACE_IGNORE_ARGS	Whether or not to omit the "args" index, and thus all the function/method arguments, to save memory.

limit

Limit the number of stack frames returned. By default (limit=0) it returns all stack frames.

Return

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

Name	Type	Description
function	string	The current function name.
line	integer	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. 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

1 · void

<?

function myfunction1($myarg1, $myarg2)
{
    $myarg1 += 1;
    $myarg2 += 1;

    myfunction2($myarg1, $myarg2);
}
function myfunction2($myarg1, $myarg2)
{
    $myarg1 += 1;
    $myarg2 += 1;

    $return = debug_backtrace();

    print_r($return);
}

myfunction1(0, 1);

?>

Array
(
    [0] => Array
        (
            [file] => /home/user/public_html/file.php
            [line] => 8
            [function] => myfunction2
            [args] => Array
                (
                    [0] => 2
                    [1] => 3
                )

        )

    [1] => Array
        (
            [file] => /home/user/public_html/file.php
            [line] => 20
            [function] => myfunction1
            [args] => Array
                (
                    [0] => 1
                    [1] => 2
                )

        )

)

2 · options · DEBUG_BACKTRACE_PROVIDE_OBJECT

<?

function myfunction1($myarg1, $myarg2)
{
    $myarg1 += 1;
    $myarg2 += 1;

    myfunction2($myarg1, $myarg2);
}
function myfunction2($myarg1, $myarg2)
{
    $myarg1 += 1;
    $myarg2 += 1;

    $options = DEBUG_BACKTRACE_PROVIDE_OBJECT;

    $return = debug_backtrace($options);

    print_r($return);
}

myfunction1(0, 1);

?>

Array
(
    [0] => Array
        (
            [file] => /home/user/public_html/file.php
            [line] => 8
            [function] => myfunction2
            [args] => Array
                (
                    [0] => 2
                    [1] => 3
                )

        )

    [1] => Array
        (
            [file] => /home/user/public_html/file.php
            [line] => 22
            [function] => myfunction1
            [args] => Array
                (
                    [0] => 1
                    [1] => 2
                )

        )

)

3 · options · DEBUG_BACKTRACE_IGNORE_ARGS

<?

function myfunction1($myarg1, $myarg2)
{
    $myarg1 += 1;
    $myarg2 += 1;

    myfunction2($myarg1, $myarg2);
}
function myfunction2($myarg1, $myarg2)
{
    $myarg1 += 1;
    $myarg2 += 1;

    $options = DEBUG_BACKTRACE_IGNORE_ARGS;

    $return = debug_backtrace($options);

    print_r($return);
}

myfunction1(0, 1);

?>

Array
(
    [0] => Array
        (
            [file] => /home/user/public_html/file.php
            [line] => 8
            [function] => myfunction2
        )

    [1] => Array
        (
            [file] => /home/user/public_html/file.php
            [line] => 22
            [function] => myfunction1
        )

)

4 · limit

<?

function myfunction1($myarg1, $myarg2)
{
    $myarg1 += 1;
    $myarg2 += 1;

    myfunction2($myarg1, $myarg2);
}
function myfunction2($myarg1, $myarg2)
{
    $myarg1 += 1;
    $myarg2 += 1;

    $options = DEBUG_BACKTRACE_PROVIDE_OBJECT;
    $limit = 1;

    $return = debug_backtrace($options, $limit);

    print_r($return);
}

myfunction1(0, 1);

?>

Array
(
    [0] => Array
        (
            [file] => /home/user/public_html/file.php
            [line] => 8
            [function] => myfunction2
            [args] => Array
                (
                    [0] => 2
                    [1] => 3
                )

        )

)