This is The ECO Library II -- Concise Edition

  It contains all functions freqently used by DOS - OS/2 programmers.
  It is not depending on any other units that SYSTEM.TPU from
  TurboPascal V6.0 or higher.
  In crossplatform development, you should therefore have not much
  troubles locating the cumbersome parts, and convert them to
  the standards requested by those environments.

  The code has been written thus, that conversion to C(++) is very
  easy. In fact, almost all little warnings and errors now
  pertain to the field of string conversion (str[0] manipulation).
  This should be solved easily.