symlink, symlinkat - make a new name for a file
Standard C library (libc, -lc)
#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() 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 (except when the
protected_symlinks feature is enabled, as explained in
proc(5)), 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.
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.
See openat(2) for an explanation of the need for symlinkat().
On success, zero is returned. On error, -1 is returned, and
errno is set to indicate the error.
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).)
(symlinkat()) linkpath is relative but
newdirfd is neither AT_FDCWD nor a valid file
descriptor.
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.
linkpath already exists.
target or linkpath points outside your accessible
address space.
An I/O error occurred.
Too many symbolic links were encountered in resolving
linkpath.
target or linkpath was too long.
A directory component in linkpath does not exist or is a
dangling symbolic link, or target or linkpath is an
empty string.
(symlinkat()) linkpath is a relative
pathname and newdirfd refers to a directory that has been
deleted.
Insufficient kernel memory was available.
The device containing the file has no room for the new directory entry.
A component used as a directory in linkpath is not, in fact,
a directory.
(symlinkat()) linkpath is relative and
newdirfd is a file descriptor referring to a file other than a
directory.
The filesystem containing linkpath does not support the
creation of symbolic links.
linkpath is on a read-only filesystem.
POSIX.1-2008.
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).