DUP(2)                  GENIX Programmer's Manual                  DUP(2)



      NAME
           dup, dup2 - duplicate an open file descriptor

      SYNOPSIS
           dup(fildes)
           int fildes;

           dup2(fildes, fildes2)
           int fildes, fildes2;

      DESCRIPTION
           Given a file descriptor returned from an open, pipe, or creat  call,
           dup  allocates another file descriptor synonymous with the original.
           The new file descriptor is returned.

           In the second form of the call, fildes is a file  descriptor  refer-
           ring  to  an  open  file, and fildes2 is a non-negative integer less
           than the maximum value allowed for file  descriptors  (approximately
           19).   Dup2  causes  fildes2 to refer to the same file as fildes. If
           fildes2 already referred to an open file, it is closed first.

      SEE ALSO
           creat(2), open(2), close(2), pipe(2)

      DIAGNOSTICS
           The value -1 is returned if: the given file descriptor  is  invalid;
           there are already too many open files.




























      Printed 11/16/83                                                        1