dpm(), other devel functions, and you

Last updated on

11 March 2021

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Have you ever tried to add something to a module, and cannot figure out why the data won't display?

You could have a typo, or could be using the wrong function to access the data, token or variable you are trying to envoke.

Devel gives you debugging tools that you can add inline to your code. Best practice suggests only using during development, using on production sites may impact site performance.

These are much more helpful than just using basic php to output variables directly, and Devel even knows to output these things to the official message area in your theme.

Basic usage: in the php file, place the variable you're curious about inside the function call. ie:

dpm($variableInQuestion);

Depending on which Devel function you use, you'll get a variety of output messages, directly on the page in question. Once you are finished debugging, remove these extra functions from your code.

Here are the functions to add to your code that will appear on your pages when Devel is enabled.

Function Name	Function Description	API 7.x	API 8.x
dpm()	Prints a variable to the 'message' area of the page.	dpm	dpm
dvm()	Displays a drupal_var_export() variable to the 'message' area of the page.	dvm	dvm
dpr()	Pretty-print a variable to the browser (no krumo).	dpr	dpr
dvr()	Like dpr(), but uses drupal_var_export() instead.	dvr	dvr
kpr()	Use Krumo to print readable output	kpr	kpr
dargs()	Prints arguments passed into the current function (variable name and value)	dargs	dargs
dd()	Drupal Debug - outputs value to a file, drupal_debug.txt, in the temp directory.	drupal_debug	dd
ddebug_backtrace()	Print function call stack	ddebug_backtrace	ddebug_backtrace