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 dup2(2)							     dup2(2)




 NAME
      dup2 - duplicate an open file descriptor to a specific slot

 SYNOPSIS
      #include <&lt&lt&lt;unistd.h>&gt&gt&gt;

      int dup2(int fildes, int fildes2);

 DESCRIPTION
      fildes is a file descriptor obtained from a creat(), open(), dup(),
      fcntl(), or pipe() system call.

      fildes2 is a non-negative integer less than the maximum value allowed
      for file descriptors.

      dup2() causes fildes2 to refer to the same file as fildes.  If fildes2
      refers to an already open file, the open file is closed first.

      The file descriptor returned by dup2() has the following in common
      with fildes:

	   +  Same open file (or pipe).

	   +  Same file pointer (that is, both file descriptors share one
	      file pointer.)

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

	   +  Same file status flags (see fcntl(2), F_DUPFD).

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

      This routine is found in the C library.  Programs using dup2() but not
      using other routines from the Berkeley importability library (such as
      the routines described in bsdproc(3C)) should not give the -lBSD
      option to ld(1).

 RETURN VALUE
      Upon successful completion, dup2() returns the new file descriptor as
      a non-negative integer, fildes2.	Otherwise, it returns -1 and sets
      errno to indicate the error.

 ERRORS
      dup2() fails if the following is true:

      [EBADF]	     fildes is not a valid open file descriptor or fildes2
		     is not in the range of legal file descriptors.

      [EINTR]	     An attempt to close fildes2 was interrupted by a
		     signal.  The file is still open.



 Hewlett-Packard Company	    - 1 -   HP-UX Release 11i: November 2000






 dup2(2)							     dup2(2)




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

 STANDARDS CONFORMANCE
      dup2(): AES, SVID2, SVID3, XPG3, XPG4, FIPS 151-2, POSIX.1

















































 Hewlett-Packard Company	    - 2 -   HP-UX Release 11i: November 2000