ttyslot.3: Fix feature test macro requirements

[thirdparty/man-pages.git] / man2 / symlink.2

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.\" This manpage is Copyright (C) 1992 Drew Eckhardt;
.\"                               1993 Michael Haardt, Ian Jackson.
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.\" Modified 1993-07-24 by Rik Faith
.\" Modified 1996-04-26 by Nick Duffek <nsd@bbc.com>
.\" Modified 1996-11-06 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 1997-01-31 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
.\"
.TH SYMLINK 2 2007-07-26 "Linux" "Linux Programmer's Manual"
.SH NAME
symlink \- make a new name for a file
.SH SYNOPSIS
.B #include <unistd.h>
.sp
.BI "int symlink(const char *" oldpath ", const char *" newpath );
.sp
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.sp
.ad l
.BR symlink ():
_BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500 || _POSIX_C_SOURCE\ >=\ 200112L
.ad b
.SH DESCRIPTION
.BR symlink ()
creates a symbolic link named
.I newpath
which contains the string
.IR oldpath .

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
.I ..
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
.RB ( S_ISVTX )
set.

If
.I newpath
exists it will
.I not
be overwritten.
.SH "RETURN VALUE"
On success, zero is returned.
On error, \-1 is returned, and
.I errno
is set appropriately.
.SH ERRORS
.TP
.B EACCES
Write access to the directory containing
.I newpath
is denied, or one of the directories in the path prefix of
.I newpath
did not allow search permission.
(See also
.BR path_resolution (7).)
.TP
.B EEXIST
.I newpath
already exists.
.TP
.B EFAULT
.IR oldpath " or " newpath " points outside your accessible address space."
.TP
.B EIO
An I/O error occurred.
.TP
.B ELOOP
Too many symbolic links were encountered in resolving
.IR newpath .
.TP
.B ENAMETOOLONG
.IR oldpath " or " newpath " was too long."
.TP
.B ENOENT
A directory component in
.I newpath
does not exist or is a dangling symbolic link, or
.I oldpath
is the empty string.
.TP
.B ENOMEM
Insufficient kernel memory was available.
.TP
.B ENOSPC
The device containing the file has no room for the new directory
entry.
.TP
.B ENOTDIR
A component used as a directory in
.I newpath
is not, in fact, a directory.
.TP
.B EPERM
The file system containing
.I newpath
does not support the creation of symbolic links.
.TP
.B EROFS
.I newpath
is on a read-only file system.
.SH "CONFORMING TO"
SVr4, 4.3BSD, POSIX.1-2001.
.\" SVr4 documents additional error codes EDQUOT and ENOSYS.
.\" See
.\" .BR open (2)
.\" re multiple files with the same name, and NFS.
.SH NOTES
No checking of
.I oldpath
is done.

Deleting the name referred to by a symlink will actually delete the
file (unless it also has other hard links).
If this behavior is not desired, use
.BR link (2).
.SH "SEE ALSO"
.BR ln (1),
.BR lchown (2),
.BR link (2),
.BR lstat (2),
.BR open (2),
.BR readlink (2),
.BR rename (2),
.BR symlinkat (2),
.BR unlink (2),
.BR path_resolution (7),
.BR symlink (7)