Cannot close ODBC connections

Question

I use odbc_connect() to open a DSN-less connection with a Microsoft Access file under PHP/5.6.21 and write into the file:

$conn = odbc_connect('DRIVER={Microsoft Access Driver (*.mdb, *.accdb)}; DBQ=D:\\Path\\To\\Output.mdb', '', '');

Apparently, both odbc_close($conn) and odbc_close_all() destroy the resource but don't really close the connection. As a result:

• I cannot move or delete the file when I'm done because I get file is in use by another process error messages.

• I cannot write as many files as I need because I get Too many client tasks.

Is it possible to effectively close an ODBC connection to Microsoft Access from PHP or the feature is just not implemented?