Please help to understand the value of slippage

 
if I set value of slippage to 0 for market order or EA, is it means not allowed to slippage? or is it means allowed unlimited slippage?
 
If I am wrong so sorry but I think it is value of the permissible slippage.
 
Sergey Golubev:
If I am wrong so sorry but I think it is value of the permissible slippage.

It does not matter, just technical discussion. so you are agreed it is allowed unlimited slippage, if you are right,  I just want know that how to setup for not allowed slippage?

Reason: