DUP(2)                     SYSTEM CALLS                    DUP(2)


NAME
     dup -- duplicate an open file descriptor


SYNOPSIS
     #include <unistd.h>
     int dup(int fildes);


SYNOPSIS <in case of float1/float2 non-ANSI C>
     int dup(fildes)
     int fildes



DESCRIPTION
     fildes  is  a  file  descriptor  obtained  from  a creat(2),
     open(2), dup(2),  fcntl(2),  or  pipe(2)  system  call.  dup
     returns a new file descriptor that has the following in com-
     mon with the original:

          The same open file (or pipe)

          The same file pointer (both file descriptors share  one
          file pointer)

          The same access mode (read, write or read/write)

     The new file descriptor is set to remain open across exec(2)
     system calls. See fcntl(2).

     The file descriptor returned is the  lowest  one  available.
     dup fails if one or more of the following are true.

     [EBADF]        fildes is not a valid open file descriptor.

     [EINTR]        A  signal  was  caught  during the dup system
                    call.

     [EMFILE]       The process/job has too many open files  [see
                    getrlimit(2)].

     [ENOLINK]      fildes  is  on a remote machine, and the link
                    to that machine is no longer active.




SEE ALSO
     close(2), creat(2),  exec(2),  fcntl(2),  open(2),  pipe(2),
     lockf(3C)






SUPER-UX            Last change: Nov 12, 1996                   1





DUP(2)                     SYSTEM CALLS                    DUP(2)


DIAGNOSTICS
     Upon  successful completion a non-negative integer (the file
     descriptor)  is  returned.  Otherwise,  a  value  of  -1  is
     returned, and errno is set to indicate the error.





















































SUPER-UX            Last change: Nov 12, 1996                   2