DUP(2)                   HP Integral PC                    DUP(2)
     DUP(2)                   HP Integral PC                    DUP(2)
     DUP(2)                   HP Integral PC                    DUP(2)
     DUP(2)                   HP Integral PC                    DUP(2)



     NAME
     NAME
     NAME
     NAME
          dup - duplicate an open file descriptor

     SYNOPSIS
     SYNOPSIS
     SYNOPSIS
     SYNOPSIS
          int dup (fildes)
          int fildes;

     DESCRIPTION
     DESCRIPTION
     DESCRIPTION
     DESCRIPTION
          Fildes is a file descriptor obtained from a creat , open ,
          dup , fcntl , or pipe system call.  Dup returns a new file
          descriptor having the following in common with the original:

               Same open file (or pipe).

               Same file pointer.  (i.e., both file descriptors share
               one file pointer.)

               Same access mode (read, write or read/write).

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

          The file descriptor returned is the lowest one available.

          Dup will fail if one or more of the following are true:

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

               Twenty (20) file descriptors are currently open.
               [EMFILE]

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

     SEE ALSO
     SEE ALSO
     SEE ALSO
     SEE ALSO
          creat(2), close(2), exec(2), fcntl(2), open(2), pipe(2).

















     Hewlett-Packard               - 1 -            (printed 12/11/84)