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symlinkat(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():
       _XOPEN_SOURCE >= 500 || _POSIX_C_SOURCE >= 200112L
           || /* Glibc versions <= 2.19: */ _BSD_SOURCE

   symlinkat():
       Since glibc 2.10:
           _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 substituted 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 nonexistent 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 pathname).

   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 symlink()).

   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  directories 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  or  linkpath  is an 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().  When linkpath is a
   relative pathname, glibc constructs a pathname based  on  the  symbolic
   link in /proc/self/fd that corresponds to the newdirfd argument.

SEE ALSO

   ln(1),  namei(1),  lchown(2),  link(2), lstat(2), open(2), readlink(2),
   rename(2), unlink(2), path_resolution(7), symlink(7)

COLOPHON

   This page is part of release 4.09 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
   https://www.kernel.org/doc/man-pages/.



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