LINKAT(2)                                           Linux Programmer's Manual                                          LINKAT(2)



NAME
       linkat - create a file link relative to directory file descriptors

SYNOPSIS
       #include <fcntl.h> /* Definition of AT_* constants */
       #include <unistd.h>

       int linkat(int olddirfd, const char *oldpath,
                  int newdirfd, const char *newpath, int flags);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       linkat():
       Since glibc 2.10: _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
       Before glibc 2.10: _ATFILE_SOURCE

DESCRIPTION
       The linkat() system call operates in exactly the same way as link(2), except for the differences described in this manual
       page.

       If the pathname given in oldpath is relative, then it is interpreted relative to the directory referred to  by  the  file
       descriptor  olddirfd (rather than relative to the current working directory of the calling process, as is done by link(2)
       for a relative pathname).

       If oldpath is relative and olddirfd is the special value AT_FDCWD, then oldpath is interpreted relative  to  the  current
       working directory of the calling process (like link(2)).

       If oldpath is absolute, then olddirfd is ignored.

       The interpretation of newpath is as for oldpath, except that a relative pathname is interpreted relative to the directory
       referred to by the file descriptor newdirfd.

       By default, linkat(), does not dereference oldpath if it is a symbolic link (like link(2)).  Since Linux 2.6.18, the flag
       AT_SYMLINK_FOLLOW  can be specified in flags to cause oldpath to be dereferenced if it is a symbolic link.  Before kernel
       2.6.18, the flags argument was unused, and had to be specified as 0.

RETURN VALUE
       On success, linkat() returns 0.  On error, -1 is returned and errno is set to indicate the error.

ERRORS
       The same errors that occur for link(2) can also occur for linkat().   The  following  additional  errors  can  occur  for
       linkat():

       EBADF  olddirfd or newdirfd is not a valid file descriptor.

       ENOTDIR
              oldpath  is  relative and olddirfd is a file descriptor referring to a file other than a directory; or similar for
              newpath and newdirfd

VERSIONS
       linkat() was added to Linux in kernel 2.6.16.

CONFORMING TO
       POSIX.1-2008.

NOTES
       See openat(2) for an explanation of the need for linkat().

SEE ALSO
       link(2), openat(2), path_resolution(7), symlink(7)

COLOPHON
       This page is part of release 3.25 of the Linux man-pages project.  A description of the project,  and  information  about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                                                      2009-12-13                                                  LINKAT(2)