/*
FUNCTION
<<rename>>---rename a file

INDEX
	rename
INDEX
	_rename_r

ANSI_SYNOPSIS
	#include <stdio.h>
	int rename(const char *<[old]>, const char *<[new]>);

	int _rename_r(void *<[reent]>, 
                      const char *<[old]>, const char *<[new]>);

TRAD_SYNOPSIS
	#include <stdio.h>
	int rename(<[old]>, <[new]>)
	char *<[old]>;
	char *<[new]>;

	int _rename_r(<[reent]>, <[old]>, <[new]>)
	char *<[reent]>;
	char *<[old]>;
	char *<[new]>;

DESCRIPTION
Use <<rename>> to establish a new name (the string at <[new]>) for a
file now known by the string at <[old]>.  After a successful
<<rename>>, the file is no longer accessible by the string at <[old]>.

If <<rename>> fails, the file named <<*<[old]>>> is unaffected.  The
conditions for failure depend on the host operating system.

The alternate function <<_rename_r>> is a reentrant version.  The
extra argument <[reent]> is a pointer to a reentrancy structure.

RETURNS
The result is either <<0>> (when successful) or <<-1>> (when the file
could not be renamed).

PORTABILITY
ANSI C requires <<rename>>, but only specifies that the result on
failure be nonzero.  The effects of using the name of an existing file
as <<*<[new]>>> may vary from one implementation to another.

Supporting OS subroutines required: <<link>>, <<unlink>>, or <<rename>>.
*/

#include <stdio.h>
#include <sys/unistd.h>
#include <reent.h>

int
_rename_r (ptr, old, new)
     struct _reent *ptr;
     _CONST char *old;
     _CONST char *new;
{
#ifdef HAVE_RENAME
  return _rename (old,new);
#else
  if (_link_r (ptr, old, new) == -1)
    return -1;

  if (_unlink_r (ptr, old) == -1)
    {
      /* ??? Should we unlink new? (rhetorical question) */
      return -1;
    }
#endif
  return 0;
}

#ifndef _REENT_ONLY

int
rename (old, new)
     _CONST char *old;
     _CONST char *new;
{
  return _rename_r (_REENT, old, new);
}

#endif