MQL4 Reference  Checkup
 Checkup  GetLastError
  GetLastError
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 | GetLastErrorReturns the contents of the system variable _LastError. 
 Returned Value Returns the value of the last error that occurred during the execution of an mql4 program. Note After the function call, the contents of _LastError are reset. For convenience, trade errors are additionally listed in the Trade Server Return Codes section. |