what is "no error" exactly?

 
My OrderSend() function just returned with an error of "no error". It returned false, but the order was opened, as the error message said. What is this exactly? Error? Or No Error?
 
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[Deleted]  
Hi Zap,

An error code of 0 means the command completed without a problem. See this page for more info: https://docs.mql4.com/constants/errors