How to print variable/debug data from your extension.php?

Question

I am trying to add a menu entry in the navigation, but this is causing the navigation menu to disappear, I am trying to debug the code but could not find any particular file.

I have checked the following:

• Browser's Javascript Console
• CiviCRM logs from ConfigAndLog folder
• Apache2 log

Is there anything else I should check? Is there any way I can print the data in the extension_civicrm_navigationMenu(&$params) function?

Answer 1

(Update) As of v4.7.0, the approaches below still work, but there's a better way to write to the log file using a PSR-3 logger, e.g.:

Civi::log()->info('Hello, log!');
Civi::log()->error('I'm sorry, {name}. I'm afraid I can't do that.', array(
  'name' => 'Stanley Kubrick',
));

See also: https://civicrm.org/blog/totten/the-static-is-dead-long-live-the-static

---

To write out to CiviCRM's ConfigAndLog folder, one can use either:

CRM_Core_Error::debug_log_message('hello log');
CRM_Core_Error::debug_var('name', $var);

There's also an experimental PSR-3 logger (CRM_Utils_SystemLogger) which writes out to the database (table civicrm_system_log), e.g.

$log = new CRM_Utils_SystemLogger();
$log->info("hello log");
$log->error("I'm sorry, {name}. I'm afraid I can't do that.", array(
  'name' => 'Stanley Kubrick',
));

If the debug statement is temporary (won't be committed/redistributed), then you can usually use CMS-specific functions (like Drupal devel's dpm() or Joomla's JLog).