Description:
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While odbc_close() warns if a resource which is not an odbc link
or an odbc link persistent resource is passed, it still goes on to
close the resource.

Test script:
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<?php

odbc_close(STDIN);
var_dump(STDIN);

Expected result:
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Warning: odbc_close(): supplied resource is not a valid ODBC-Link resource in %s on line 3
bool(false)
resource(1) of type (stream)

Actual result:
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Warning: odbc_close(): supplied resource is not a valid ODBC-Link resource in $s on line 3
NULL
resource(1) of type (Unknown)