(PHP 5, PHP 7, PHP 8)
Exception::getTrace — 获取异常追踪信息
返回异常追踪信息。
此函数没有参数。
返回包含异常追踪信息的数组（array）。
Example #1 Exception::getTrace()示例
<?php
function test() {
throw new Exception;
}
try {
test();
} catch(Exception $e) {
var_dump($e->getTrace());
}
?>
以上例程的输出类似于：
array(1) {
[0]=>
array(4) {
["file"]=>
string(22) "/home/bjori/tmp/ex.php"
["line"]=>
int(7)
["function"]=>
string(4) "test"
["args"]=>
array(0) {
}
}
}
If you are wanting to see the args within a stack trace on PHP 7.4, note that there is now a zend flag in the php.ini file that is default set to Off.
zend.exception_ignore_args = Off
Set this flag to On and it will show the args again.
zend.exception_ignore_args = On
https://www.php.net/manual/en/ini.core.php#ini.zend.exception-ignore-args
As of PHP 7.4 return values of Exception::getTrace() (and Error::getTrace()) no longer contains "args" keys like debug_backtrace() with default options.
So, return value since 7.4 is like debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS).
The order of the trace starts at the source of the exception and does not include main.
So for example:
<?php
function Bar() {
throw new Exception;
}
function Foo() {
Bar();
}
try {
Foo();
} catch(Exception $e) {
var_dump($e->getTrace());
}
?>
Will output:
array(2) {
[0]=>
array(4) {
["file"]=>
string(21) "/.../test.php"
["line"]=>
int(8)
["function"]=>
string(3) "Bar"
["args"]=>
array(0) {
}
}
[1]=>
array(4) {
["file"]=>
string(21) "/.../test.php"
["line"]=>
int(12)
["function"]=>
string(3) "Foo"
["args"]=>
array(0) {
}
}
}
Two important points about this function which are not documented:
1) The trace does not include the file / line at which the exception is thrown; that entry is only recorded in the top-level getFile/Line methods.
2) Elements are returned in 'closest-first' order, e.g. if you have a script x which calls function y which calls function z which throws an exception, then the first trace element will be 'Y' and the second will be 'X'.
When calling getTrace(), there is also the name of the class in returned array:
<?php
class Test {
function __construct() {
throw new Exception('FATAL ERROR: bla bla...');
}
}
try {
$obj = new Test();
} catch(Exception $e) {
var_dump($e->getTrace());
}
?>
Will show something like:
array(1) {
[0]=> array(6) {
["file"]=> string(54) "/....../test.php"
["line"]=> int(37)
["function"]=> string(11) "__construct"
["class"]=> string(4) "Test"
["type"]=> string(2) "->"
["args"]=> array(0) { }
}
}
You can use this function to format a exception:
<?php
function MakePrettyException(Exception $e) {
$trace = $e->getTrace();
$result = 'Exception: "';
$result .= $e->getMessage();
$result .= '" @ ';
if($trace[0]['class'] != '') {
$result .= $trace[0]['class'];
$result .= '->';
}
$result .= $trace[0]['function'];
$result .= '();<br />';
return $result;
}
//Example:
try {
$obj = new Test();
} catch(Exception $e) {
echo MakePrettyException($e);
}
?>
Result:
Exception: "FATAL ERROR: bla bla..." @ Test->__construct();