Get filename of file which ran PHP include

Question

When using the PHP include, how can I find out which file is calling the include? In short, what is the parent's file filename?

Answer 1

An easy way is to assign a variable in the parent file (before the inclue), then reference that variable in the included file.

Parent File:

$myvar_not_replicated = __FILE__; // Make sure nothing else is going to overwrite
include 'other_file.php';

Included File:

if (isset($myvar_not_replicated)) echo "{$myvar_not_replicated} included me";
else echo "Unknown file included me";

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You could also mess around with get_included_files() or debug_backtrace() and find the event when and where the file got included, but that can get a little messy and complicated.