compiler/clib/dup.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     ANSI C function dup().
   6 */
   7
   8 #include <errno.h>
   9 #include "__open.h"
  10
  11 /*****************************************************************************
  12
  13     NAME */
  14 #include <unistd.h>
  15
  16         int dup (
  17
  18 /*  SYNOPSIS */
  19         int oldfd
  20         )
  21
  22 /*  FUNCTION
  23         Duplicates a file descriptor.
  24
  25         The object referenced by the descriptor does not distinguish between oldd
  26         and newd in any way.  Thus if newd and oldd are duplicate references to
  27         an open file, read(),  write() and lseek() calls all move a single
  28         pointer into the file, and append mode, non-blocking I/O and asynchronous
  29         I/O options are shared between the references.  If a separate pointer
  30         into the file is desired, a different object reference to the file must be
  31         obtained by issuing an additional open(2) call.  The close-on-exec flag
  32         on the new file descriptor is unset.
  33
  34     INPUTS
  35         oldfd - The file descriptor to be duplicated
  36
  37     RESULT
  38         -1 for error or the new descriptor.
  39
  40         The new descriptor returned by the call is the lowest numbered
  41         descriptor currently not in use by the process.
  42
  43     NOTES
  44         This function must not be used in a shared library or
  45         in a threaded application.
  46
  47     EXAMPLE
  48
  49     BUGS
  50
  51     SEE ALSO
  52          accept(),  open(),  close(),  fcntl(),  pipe(),  socket()
  53
  54     INTERNALS
  55
  56 ******************************************************************************/
  57 {
  58     return dup2(oldfd, __getfirstfd(0));
  59 }
  60