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



NAME
       symlink, symlinkat - make a new name for a file

SYNOPSIS
       #include <unistd.h>

       int symlink(const char *target, const char *linkpath);

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

       int symlinkat(const char *target, int newdirfd, const char *linkpath);

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

       symlink():
           _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED ||
           _POSIX_C_SOURCE >= 200112L

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

DESCRIPTION
       symlink() creates a symbolic link named linkpath which contains the string target.

       Symbolic links are interpreted at run time as if the contents of the link had been substi‐
       tuted into the path being followed to find a file or directory.

       Symbolic  links  may contain ..  path components, which (if used at the start of the link)
       refer to the parent directories of that in which the link resides.

       A symbolic link (also known as a soft link) may point to an existing file or to a nonexis‐
       tent one; the latter case is known as a dangling link.

       The permissions of a symbolic link are irrelevant; the ownership is ignored when following
       the link, but is checked when removal or renaming of the link is requested and the link is
       in a directory with the sticky bit (S_ISVTX) set.

       If linkpath exists, it will not be overwritten.

   symlinkat()
       The  symlinkat() system call operates in exactly the same way as symlink(), except for the
       differences described here.

       If the pathname given in linkpath is relative, then it  is  interpreted  relative  to  the
       directory referred to by the file descriptor newdirfd (rather than relative to the current
       working directory of the calling process, as is done by symlink()  for  a  relative  path‐
       name).

       If  linkpath  is  relative  and  newdirfd  is the special value AT_FDCWD, then linkpath is
       interpreted relative to the current working directory of the calling  process  (like  sym‐
       link()).

       If linkpath is absolute, then newdirfd is ignored.

RETURN VALUE
       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

ERRORS
       EACCES Write access to the directory containing linkpath is denied, or one of the directo‐
              ries in the path prefix of linkpath did not allow  search  permission.   (See  also
              path_resolution(7).)

       EDQUOT The  user's quota of resources on the filesystem has been exhausted.  The resources
              could be inodes or disk blocks, depending on the filesystem implementation.

       EEXIST linkpath already exists.

       EFAULT target or linkpath points outside your accessible address space.

       EIO    An I/O error occurred.

       ELOOP  Too many symbolic links were encountered in resolving linkpath.

       ENAMETOOLONG
              target or linkpath was too long.

       ENOENT A directory component in linkpath does not exist or is a dangling symbolic link, or
              target is the empty string.

       ENOMEM Insufficient kernel memory was available.

       ENOSPC The device containing the file has no room for the new directory entry.

       ENOTDIR
              A component used as a directory in linkpath is not, in fact, a directory.

       EPERM  The filesystem containing linkpath does not support the creation of symbolic links.

       EROFS  linkpath is on a read-only filesystem.

       The following additional errors can occur for symlinkat():

       EBADF  newdirfd is not a valid file descriptor.

       ENOENT linkpath  is  a  relative pathname and newdirfd refers to a directory that has been
              deleted.

       ENOTDIR
              linkpath is relative and newdirfd is a file descriptor referring to  a  file  other
              than a directory.

VERSIONS
       symlinkat()  was  added  to  Linux in kernel 2.6.16; library support was added to glibc in
       version 2.4.

CONFORMING TO
       symlink(): SVr4, 4.3BSD, POSIX.1-2001, POSIX.1-2008.

       symlinkat(): POSIX.1-2008.

NOTES
       No checking of target is done.

       Deleting the name referred to by a symbolic link will actually delete the file (unless  it
       also has other hard links).  If this behavior is not desired, use link(2).

   Glibc notes
       On  older  kernels where symlinkat() is unavailable, the glibc wrapper function falls back
       to the use of symlink(2).  When linkpath is a relative pathname, glibc constructs a  path‐
       name  based  on  the symbolic link in /proc/self/fd that corresponds to the newdirfd argu‐
       ment.

SEE ALSO
       ln(1), lchown(2), link(2), lstat(2), open(2), readlink(2), rename(2), unlink(2), path_res‐
       olution(7), symlink(7)

COLOPHON
       This  page  is  part of release 3.74 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at http://www.kernel.org/doc/man-pages/.



Linux                                       2014-08-19                                 SYMLINK(2)