I've been using the Devel module for a couple of years now but every time I try to get a backtrace I run into issues. I remember getting it working once, but I don't remember how.

It seems like using dpm(ddebug_backtrace()); should do the trick. I have tried it with no argument, TRUE, and FALSE, and I have also tried removing the dpm function it's wrapped in.

I have dpm calls directly above and below this code that print variables appropriately, but the most I get out of dpm(ddebug_backtrace()); is a blank line in the Krumo output.

Suggestions mightily appreciated.

  • dpm(ddebug_backtrace()); works fine for me (I just tried it). Does die(ddebug_backtrace()); work for you?
    – Felix Eve
    Apr 24, 2015 at 1:00

3 Answers 3


If you see the source, you can see that ddebug_backtrace() only returns values if the variable error_level is set to 1 or greater.

// Show message if error_level is ERROR_REPORTING_DISPLAY_SOME or higher.
// (This is Drupal's error_level, which is different from $error_level,
// and we purposely ignore the difference between _SOME and _ALL,
// see #970688!)
if (variable_get('error_level', 1) >= 1) {

So one of the ways to make it return values is by either changing the error_level from admin/config/development/logging, or change it temporarily in the code like so:

variable_set('error_level', 1);
variable_set('error_level', 1);

As Ian Bullock says, debug_backtrace() would return values because it ignores the variable and the content is essentially the same. But ddebug_backtrace() returns a more readable output.

  • Thank you very much for the explanation, this actually answers the question.
    – Darvanen
    Jul 28, 2016 at 0:14

For me the command had to be called without the extra d


  • This worked for me. I'm on D7.
    – jdhildeb
    Jan 21, 2016 at 17:38

In the instances where I've been like, "WTF! Where's my dpm output at?", it's either been:

  1. A permissions issue with an impersonated user not having access devel information perm.
  2. A theme page that isn't outputting the $messages var.

Hope that helps.

  • 2
    Thanks shawn, gets a vote because it's good advice, sadly I've already been through that. As I said, dpm is outputting fine but not when used with ddebug_backtrace().
    – Darvanen
    Apr 24, 2015 at 4:49

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