Sorrry you feel that way, but as I said on the Github ticket those functions were clearly marked as being just for that plugin. If you do non-standard things in plugins there is always a possibility something could break in a future version.
In your plugin you are not using the error messages it returns so you don't even need the function call, you can just replace it with a simple if clause checking the length.
$length = qa_strlen($checkvalue);
if ($length < 1 || $length > QA_DB_MAX_CONTENT_LENGTH) {
// errors
}
