델파이 코리아에서 퍼왔슴다..

void __fastcall TForm1::Button1Click(TObject *Sender)
  {
      DWORD dwSize = MAX_COMPUTERNAME_LENGTH + 1;
      char szBuf[MAX_COMPUTERNAME_LENGTH + 1];
      szBuf[0] = '\0';

      GetComputerName(szBuf, &dwSize);

      Label1->Caption = szBuf;
  }


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