symlink(2) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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

NAME         top

       symlink, symlinkat - make a new name for a file

SYNOPSIS         top

       #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         top

       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         top

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

ERRORS         top

       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         top

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

CONFORMING TO         top

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

       symlinkat(): POSIX.1-2008.

NOTES         top

       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         top

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

COLOPHON         top

       This page is part of release 5.10 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/.

Linux                          2017-09-15                     SYMLINK(2)

Pages that refer to this page: ln(1)fcntl(2)link(2)open(2)readlink(2)rename(2)syscalls(2)proc(5)inotify(7)signal-safety(7)symlink(7)