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* REQUIRED: Non-printable characters were found in the 'functions.php' file. You may want to check this file for errors.

What are non-printable characters and how can I correct it?

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Is Theme Check not indicating the line(s) in functions.php on which it is finding the non-printable characters? – Chip Bennett May 30 '11 at 13:02

They are characters that are non printable and should be removed. This is usually the first 32 ASCII characters + 127 ( it might also be extended characters above 127), for example character 7 is an "audible bell", so ya that's not going to work :)

Display (or web friendly) characters start at character 33, so look in your functions.php for some weird ASCII and delete them. Turn on debugging so you get a better error with the actual line call.

If you can't delete them you can use a preg_replace php function, something like http://stackoverflow.com/questions/1176904/php-how-to-remove-all-non-printable-characters-in-a-string.

For reference on first 127 ASCII: http://www.telacommunications.com/nutshell/ascii.htm

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