Originální popis anglicky:
symlink - make a symbolic link to a file
Návod, kniha: POSIX Programmer's Manual
#include <unistd.h>
int symlink(const char *
path1, const char
*path2);
The
symlink() function shall create a symbolic link called
path2
that contains the string pointed to by
path1 (
path2 is the name
of the symbolic link created,
path1 is the string contained in the
symbolic link).
The string pointed to by
path1 shall be treated only as a character
string and shall not be validated as a pathname.
If the
symlink() function fails for any reason other than [EIO], any file
named by
path2 shall be unaffected.
Upon successful completion,
symlink() shall return 0; otherwise, it shall
return -1 and set
errno to indicate the error.
The
symlink() function shall fail if:
- EACCES
- Write permission is denied in the directory where the
symbolic link is being created, or search permission is denied for a
component of the path prefix of path2.
- EEXIST
- The path2 argument names an existing file or
symbolic link.
- EIO
- An I/O error occurs while reading from or writing to the
file system.
- ELOOP
- A loop exists in symbolic links encountered during
resolution of the path2 argument.
- ENAMETOOLONG
- The length of the path2 argument exceeds {PATH_MAX}
or a pathname component is longer than {NAME_MAX} or the length of the
path1 argument is longer than {SYMLINK_MAX}.
- ENOENT
- A component of path2 does not name an existing file
or path2 is an empty string.
- ENOSPC
- The directory in which the entry for the new symbolic link
is being placed cannot be extended because no space is left on the file
system containing the directory, or the new symbolic link cannot be
created because no space is left on the file system which shall contain
the link, or the file system is out of file-allocation resources.
- ENOTDIR
- A component of the path prefix of path2 is not a
directory.
- EROFS
- The new symbolic link would reside on a read-only file
system.
The
symlink() function may fail if:
- ELOOP
- More than {SYMLOOP_MAX} symbolic links were encountered
during resolution of the path2 argument.
- ENAMETOOLONG
- As a result of encountering a symbolic link in resolution
of the path2 argument, the length of the substituted pathname
string exceeded {PATH_MAX} bytes (including the terminating null byte), or
the length of the string pointed to by path1 exceeded
{SYMLINK_MAX}.
The following sections are informative.
None.
Like a hard link, a symbolic link allows a file to have multiple logical names.
The presence of a hard link guarantees the existence of a file, even after the
original name has been removed. A symbolic link provides no such assurance; in
fact, the file named by the
path1 argument need not exist when the link
is created. A symbolic link can cross file system boundaries.
Normal permission checks are made on each component of the symbolic link
pathname during its resolution.
Since IEEE Std 1003.1-2001 does not require any association of
file times with symbolic links, there is no requirement that file times be
updated by
symlink().
None.
lchown() ,
link() ,
lstat() ,
open() ,
readlink() ,
unlink() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<unistd.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
