SysUtils.RaiseLastOSError Function

Raises an exception for the last occurring OS or system library error.

Pascal

procedure RaiseLastOSError; overload;
procedure RaiseLastOSError(LastError: Integer); overload;

C++

RaiseLastOSError();
RaiseLastOSError(int LastError);

File

SysUtils

Description

Call RaiseLastOSError to raise an EOSError exception for the last OS API call that failed. RaiseLastOSError retrieves the code for the last occurring API call error, if any. If this belongs to a previously occurring error, RaiseLastOSError raises an EOSError exception with the error code and message associated with that error.

C++ Examples:

Copy Code

//
//This code demonstrates the use of system error codes
//and how to use transform them into C++ exceptions.
//
void __fastcall TForm2::btRaiseLastClick(TObject *Sender)
{
    /* Set the last OS error to a bogus value */
    System::SetLastError(ERROR_ACCESS_DENIED);

    try
    {
        RaiseLastOSError();
    }
    catch(EOSError* ex)
    {
        MessageDlg(String("Caught an OS error with code: ") +
            IntToStr((int)ex->ErrorCode), mtError,
            TMsgDlgButtons() << mbOK, 0);
    }


    /* Let the Delphi's Exception dialog pop-up */
    RaiseLastOSError(ERROR_NOT_ENOUGH_MEMORY);

    /* Finally set the last error to none */
    System::SetLastError(ERROR_SUCCESS);

    if (GetLastError() != ERROR_SUCCESS)
        MessageDlg(String("Whoops, something went wrong ") +
          " in the mean time!", mtError, TMsgDlgButtons() << mbOK, 0);

    /* No exception should be thrown here */
    RaiseLastOSError();
}

Delphi Examples:

Copy Code

{
This code demonstrates the use of system error codes
and how to transform them into Delphi exceptions.
}
procedure TForm2.btRaiseLastClick(Sender: TObject);
begin
  { Set the last OS error to a bogus value }
  System.SetLastError(ERROR_ACCESS_DENIED);

  try
    RaiseLastOSError();
  except
    on Ex : EOSError do
       MessageDlg('Caught an OS error with code: ' +
          IntToStr(Ex.ErrorCode), mtError, [mbOK], 0);
  end;

  { Let the Delphi's Exception dialog pop-up }
  RaiseLastOSError(ERROR_NOT_ENOUGH_MEMORY);

  { Finally set the last error to none }
  System.SetLastError(ERROR_SUCCESS);

  if GetLastError() <> ERROR_SUCCESS then
     MessageDlg('Whoops, something went wrong in the ' +
                'mean time!', mtError, [mbOK], 0);

  { No exception should be thrown here }
  RaiseLastOSError();
end;