symlink

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():
           _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 ig-
       nored  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 sym-
       link(), 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  ex-
              hausted.   The resources could be inodes or disk blocks, depend-
              ing 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  dan-
              gling 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  direc-
              tory 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  rela-
       tive  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 5.05 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)