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PHP debug_backtrace() Function

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Example

Generate a PHP backtrace:

<?php
function a($txt) {
    b("Glenn");
}
function b($txt) {
    c("Cleveland");
}
function c($txt) {
    var_dump(debug_backtrace());
}
a("Peter");
?>

The above code will output something like this:

Array (
    [0] => Array (
        [file] => C:\webfolder\test.php
        [line] => 6
        [function] => c
        [args] => Array (
            [0] => Cleveland
        )
    )
    [1] => Array (
        [file] => C:\webfolder\test.php
        [line] => 3
        [function] => b
        [args] => Array (
            [0] => Glenn
        )
    )
    [2] => Array (
        [file] => C:\webfolder\test.php
        [line] => 11
        [function] => a
        [args] => Array (
            [0] => Peter
        )
    )
)


Definition and Usage

The debug_backtrace() function generates a PHP backtrace.

This function displays data from the code that led up to the debug_backtrace() function.

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

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. Possible calls:
  • Returns: "->"  - Method call
  • Returns: "::"  - Static method call
  • Returns nothing - Function call
args array If inside a function, it lists the functions arguments. If inside an included file, it lists the included file names

Syntax

debug_backtrace(options,limit);

Parameter Description
options

Optional. Specifies a bitmask for the following 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 all the function/method arguments, to save memory)

limit Optional. Limits the number of stack frames printed. By default (limit=0) it prints all stack frames

Technical Details

Return Value: None
PHP Version: 4.3+
PHP Changelog: PHP 5.4: The optional parameter limit was added
PHP 5.3.6: The parameter provide_object was changed to options and additional option DEBUG_BACKTRACE_IGNORE_ARGS is added
PHP 5.2.5: The optional parameter provide_object was added
PHP 5.1.1: Added the current object as a possible return element

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