/sys$common/syshlp/helplib.hlb CC, Run-time functions, dup2  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Makes file_descriptor_2 point to the same file as
  file_descriptor_1.

  Syntax:

       #include <unixio.h>

       int dup2(int file_descriptor_1, int file_descriptor_2);