GetUserName

This code demonstrates how to obtain the name of the user currently logged on to this machine. Again, this code really doesn't depict an advanced topic, rather it represents a useful code sample that is regularly used across separate projects.

const
  sNoUserNameError = 'There was an error determining the identity of
                     'the current user.'
 
function GetUserName: string;
var lpBuffer: array of char;
    dwBufferSize: DWORD;
begin
  dwBufferSize := 0;
  // When called with null parameters, GetUserName returns the
  // actual size required for the outgoing buffer, including
  // the terminating null character.
  Windows.GetUserName(@lpBuffer, dwBufferSize);
  if dwBufferSize = 0 then
    raise Exception.Create(sNoUserNameError);
  SetLength(lpBuffer, dwBufferSize);
  Win32Check(Windows.GetUserName(@lpBuffer[0], dwBufferSize));
  Result := pChar(@lpBuffer[0]);
end;
 

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