debug_print_backtrace

(PHP 5, PHP 7, PHP 8)

debug_print_backtrace — 打印一条回溯。

说明

debug_print_backtrace(int $options = 0, int $limit = 0): void

debug_print_backtrace() 打印了一条 PHP 回溯。它打印了函数调用、被 included/required 的文件和 eval() 的代码。

参数

options

这个参数是以下选项的位掩码：

**debug_print_backtrace()** 选项
DEBUG_BACKTRACE_IGNORE_ARGS	是否忽略 "args" 的索引，包括所有的 function/method 的参数，能够节省内存开销。

limit

这个参数能够用于限制返回堆栈帧的数量。默认为 (limit=0) ，返回所有的堆栈帧。

返回值

没有返回值。

示例

示例 #1 debug_print_backtrace() 范例

<?php
/ include.php file

function a() {
    b();
}

function b() {
    c();
}

function c(){
    debug_print_backtrace();
}

a();

?>

<?php
/ 文件 test.php
/ 这是你应该运行的文件

include 'include.php';
?>

以上示例的输出类似于：

#0  c() called at [/tmp/include.php:10]
#1  b() called at [/tmp/include.php:6]
#2  a() called at [/tmp/include.php:17]
#3  include(/tmp/include.php) called at [/tmp/test.php:3]

参见

debug_backtrace() - 产生一条回溯跟踪(backtrace)

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＋添加备注

用户贡献的备注 4 notes

down

bishop ¶

15 years ago

Another way to manipulate and print a backtrace, without using output buffering:

<?php
/ print backtrace, getting rid of repeated absolute path on each file
$e = new Exception();
print_r(str_replace('/path/to/code/', '', $e->getTraceAsString()));
?>

down

dany dot dylan at gmail dot com ¶

16 years ago

I like the output of debug_print_backtrace() but I sometimes want it as a string.



bortuzar's solution to use output buffering is great, but I'd like to factorize that into a function.  Doing that however always results in whatever function name I use appearing at the top of the stack which is redundant.



Below is my noddy (simple) solution.  If you don't care for renumbering the call stack, omit the second preg_replace().



<?php

    function debug_string_backtrace() {

        ob_start();

        debug_print_backtrace();

        $trace = ob_get_contents();

        ob_end_clean();



        / Remove first item from backtrace as it's this function which

        / is redundant.

        $trace = preg_replace ('/^#0\s+' . __FUNCTION__ . "[^\n]*\n/", '', $trace, 1);



        / Renumber backtrace items.

        $trace = preg_replace ('/^#(\d+)/me', '\'#\' . ($1 - 1)', $trace);



        return $trace;

    }

?>

down

sun at drupal dot org ¶

6 months ago

If you see string arguments and parameters getting cut off like this:

#0 hook.php(324): output_notice('checkout_before...')
#1 hook.php(348): invoke_hook('checkout_before...', Array)

You can increase the maximum length of arguments and parameters in the printed trace through an PHP INI setting:

<?php
ini_set('zend.exception_string_param_max_len', 100);
debug_print_backtrace();
?>

…so you can read the full arguments:

#0 hook.php(324): output_notice('checkout_before_payment')
#1 hook.php(348): invoke_hook('checkout_before_payment', Array)

In edge cases, it might even uncover nested traces that you didn't notice before.

down

-1

David Spector ¶

4 years ago

If your show your error messages in HTML (with suitable safety using entities), this function won't work nicely because it uses newlines for formatting.

Here is a function that works similarly, but using <BR> tags. Insert it near the beginning of your program to add a stack to Warning output only, or modify it as you like:

/ Here is code for error stack output in HTML:
function error_handler_callback($errno,$message,$file,$line,$context)
    {
    if ($errno === E_WARNING)
        echo "Stack, innermost first:<br>".nl2br((new Exception())->getTraceAsString());
    return false; / to execute the regular error handler
    }
set_error_handler("error_handler_callback");