freebsd-skq/lib/libc/sys/symlink.2

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.\"     @(#)symlink.2	8.1 (Berkeley) 6/4/93
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.Dd April 10, 2008
.Dt SYMLINK 2
.Os
.Sh NAME
.Nm symlink ,
.Nm symlinkat
.Nd make symbolic link to a file
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn symlink "const char *name1" "const char *name2"
.Ft int
.Fn symlinkat "const char *name1" "int fd" "const char *name2"
.Sh DESCRIPTION
A symbolic link
.Fa name2
is created to
.Fa name1
.Fa ( name2
is the name of the
file created,
.Fa name1
is the string
used in creating the symbolic link).
Either name may be an arbitrary path name; the files need not
be on the same file system.
.Pp
The
.Fn symlinkat
system call is equivalent to
.Fn symlink
except in the case where
.Fa name2
specifies a relative path.
In this case the symbolic link is created relative to the directory
associated with the file descriptor
.Fa fd
instead of the current working directory.
If
.Fn symlinkat
is passed the special value
.Dv AT_FDCWD
in the
.Fa fd
parameter, the current working directory is used and the behavior is
identical to a call to
.Fn symlink .
.Sh RETURN VALUES
.Rv -std symlink
.Sh ERRORS
The symbolic link succeeds unless:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the
.Fa name2
path prefix is not a directory.
.It Bq Er ENAMETOOLONG
A component of the
.Fa name2
pathname exceeded 255 characters,
or the entire length of either path name exceeded 1023 characters.
.It Bq Er ENOENT
A component of the
.Fa name2
path prefix does not exist.
.It Bq Er EACCES
A component of the
.Fa name2
path prefix denies search permission, or write permission is denied on the
parent directory of the file to be created.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the
.Fa name2
path name.
.It Bq Er EEXIST
The path name pointed at by the
.Fa name2
argument
already exists.
.It Bq Er EPERM
The parent directory of the file named by
.Fa name2
has its immutable flag set, see the
.Xr chflags 2
manual page for more information.
.It Bq Er EIO
An I/O error occurred while making the directory entry for
.Fa name2 ,
or allocating the inode for
.Fa name2 ,
or writing out the link contents of
.Fa name2 .
.It Bq Er EROFS
The file
.Fa name2
would reside on a read-only file system.
.It Bq Er ENOSPC
The directory in which the entry for the new symbolic link is being placed
cannot be extended because there is no space left on the file
system containing the directory.
.It Bq Er ENOSPC
The new symbolic link cannot be created because
there is no space left on the file
system that will contain the symbolic link.
.It Bq Er ENOSPC
There are no free inodes on the file system on which the
symbolic link is being created.
.It Bq Er EDQUOT
The directory in which the entry for the new symbolic link
is being placed cannot be extended because the
user's quota of disk blocks on the file system
containing the directory has been exhausted.
.It Bq Er EDQUOT
The new symbolic link cannot be created because the user's
quota of disk blocks on the file system that will
contain the symbolic link has been exhausted.
.It Bq Er EDQUOT
The user's quota of inodes on the file system on
which the symbolic link is being created has been exhausted.
.It Bq Er EIO
An I/O error occurred while making the directory entry or allocating the inode.
.It Bq Er EFAULT
The
.Fa name1
or
.Fa name2
argument
points outside the process's allocated address space.
.El
.Pp
In addition to the errors returned by the
.Fn symlink ,
the
.Fn symlinkat
may fail if:
.Bl -tag -width Er
.It Bq Er EBADF
The
.Fa name2
argument does not specify an absolute path and the
.Fa fd
argument is neither
.Dv AT_FDCWD
nor a valid file descriptor open for searching.
.It Bq Er ENOTDIR
The
.Fa name2
argument is not an absolute path and
.Fa fd
is neither
.Dv AT_FDCWD
nor a file descriptor associated with a directory.
.El
.Sh SEE ALSO
.Xr ln 1 ,
.Xr chflags 2 ,
.Xr link 2 ,
.Xr lstat 2 ,
.Xr readlink 2 ,
.Xr unlink 2 ,
.Xr symlink 7
.Sh STANDARDS
The
.Fn symlinkat
system call follows The Open Group Extended API Set 2 specification.
.Sh HISTORY
The
.Fn symlink
system call appeared in
.Bx 4.2 .
The
.Fn symlinkat
system call appeared in
.Fx 8.0 .