Fatal error Online Find the answer is not solve the solution

Fatal error on the Internet to find the answer can not solve
Error message:
Fatal error:call to undefined function querymysql () inch E:\xampp\htdocs\business\include\days_mgmt.php on line 7
Code:

PHP Code

I do not have to configure PHP MySQL environment, is the download xampp.
The key is, I have been writing for several months, has been so written, did not appear this problem, should not be the configuration problem it!
Querymysql () is lib/function.php inside, I also include in the beginning.

What the hell is going on???? Big boys!

------Solution--------------------
So you're
$result =querymysql ($query); Ago
Add a sentence of Print_r (Get_included_files ());

See if lib/function.php is in there.

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