Manual Pages for UNIX Operating System command usage for man dup

System Calls                                               dup(2)



NAME
     dup - duplicate an open file descriptor

SYNOPSIS
     #include 

     int dup(int fildes);


DESCRIPTION
     The dup() function returns a new file descriptor having  the
     following  in  common with the original open file descriptor
     fildes:

         o    same open file (or pipe)

         o    same file pointer (that is, both  file  descriptors
              share one file pointer)

         o    same access mode (read, write or read/write).


     The new file descriptor is set to remain  open  across  exec
     functions (see fcntl(2)).


     The file descriptor returned is the lowest one available.


     The dup(fildes) function call is equivalent to:


     fcntl(fildes, F_DUPFD, 0)

RETURN VALUES
     Upon   successful   completion,   a   non-negative   integer
     representing  the file descriptor is returned. Otherwise, -1
     is returned and errno is set to indicate the error.

ERRORS
     The dup() function will fail if:

     EBADF      The fildes argument is  not  a  valid  open  file
                descriptor.


     EINTR      A signal was caught during the execution  of  the
                dup() function.


     EMFILE     The  process  has  too  many  open   files   (see
                getrlimit(2)).



SunOS 5.11          Last change: 28 Dec 1996                    1






System Calls                                               dup(2)



     ENOLINK    The fildes argument is on a  remote  machine  and
                the link to that machine is no longer active.


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | Async-Signal-Safe           |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     close(2),   creat(2),   exec(2),   fcntl(2),   getrlimit(2),
     open(2),  pipe(2), dup2(3C), lockf(3C), attributes(5), stan-
     dards(5)






























SunOS 5.11          Last change: 28 Dec 1996                    2