Print PHP Call Stack

Print PHP Call Stack

If you want to generate a backtrace, you are looking for debug_backtrace and/or debug_print_backtrace.

The first one will, for instance, get you an array like this one (quoting the manual) :

array(2) {
[0]=>
array(4) {
    ["file"] => string(10) "/tmp/a.php"
    ["line"] => int(10)
    ["function"] => string(6) "a_test"
    ["args"]=>
    array(1) {
      [0] => &string(6) "friend"
    }
}
[1]=>
array(4) {
    ["file"] => string(10) "/tmp/b.php"
    ["line"] => int(2)
    ["args"] =>
    array(1) {
      [0] => string(10) "/tmp/a.php"
    }
    ["function"] => string(12) "include_once"
  }
}

They will apparently not flush the I/O buffer, but you can do that yourself, with flush and/or ob_flush.

(see the manual page of the first one to find out why the "and/or" ;-) )

debug_print_backtrace() to String for log-file

Use another function. debug_backtrace() returns an array that you can loop through, format and save:

$data = debug_backtrace();

Or use output buffering for the formatted output string:

ob_start();
debug_print_backtrace();
$data = ob_get_clean();

How can I get the call stack from a Fatal Error?

I would recommend installing Xdebug on your development server. It's a very valuable tool in cases like these.

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