mirror of https://github.com/mkerrisk/man-pages
127 lines
4.3 KiB
Plaintext
127 lines
4.3 KiB
Plaintext
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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "SYMLINK" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" symlink
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.SH NAME
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symlink \- make a symbolic link to a file
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.SH SYNOPSIS
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.LP
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\fB#include <unistd.h>
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.br
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.sp
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int symlink(const char *\fP\fIpath1\fP\fB, const char *\fP\fIpath2\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The \fIsymlink\fP() function shall create a symbolic link called \fIpath2\fP
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that contains the string pointed to by
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\fIpath1\fP ( \fIpath2\fP is the name of the symbolic link created,
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\fIpath1\fP is the string contained in the symbolic
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link).
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.LP
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The string pointed to by \fIpath1\fP shall be treated only as a character
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string and shall not be validated as a pathname.
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.LP
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If the \fIsymlink\fP() function fails for any reason other than [EIO],
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any file named by \fIpath2\fP shall be unaffected.
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.SH RETURN VALUE
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.LP
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Upon successful completion, \fIsymlink\fP() shall return 0; otherwise,
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it shall return -1 and set \fIerrno\fP to indicate the
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error.
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.SH ERRORS
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.LP
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The \fIsymlink\fP() function shall fail if:
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.TP 7
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.B EACCES
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Write permission is denied in the directory where the symbolic link
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is being created, or search permission is denied for a
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component of the path prefix of \fIpath2\fP.
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.TP 7
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.B EEXIST
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The \fIpath2\fP argument names an existing file or symbolic link.
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.TP 7
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.B EIO
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An I/O error occurs while reading from or writing to the file system.
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.TP 7
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.B ELOOP
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A loop exists in symbolic links encountered during resolution of the
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\fIpath2\fP argument.
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.TP 7
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.B ENAMETOOLONG
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The length of the \fIpath2\fP argument exceeds {PATH_MAX} or a pathname
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component is longer than {NAME_MAX} or the length of the
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\fIpath1\fP argument is longer than {SYMLINK_MAX}.
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.TP 7
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.B ENOENT
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A component of \fIpath2\fP does not name an existing file or \fIpath2\fP
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is an empty string.
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.TP 7
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.B ENOSPC
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The directory in which the entry for the new symbolic link is being
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placed cannot be extended because no space is left on the
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file system containing the directory, or the new symbolic link cannot
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be created because no space is left on the file system which
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shall contain the link, or the file system is out of file-allocation
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resources.
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.TP 7
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.B ENOTDIR
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A component of the path prefix of \fIpath2\fP is not a directory.
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.TP 7
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.B EROFS
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The new symbolic link would reside on a read-only file system.
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.sp
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.LP
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The \fIsymlink\fP() function may fail if:
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.TP 7
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.B ELOOP
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More than {SYMLOOP_MAX} symbolic links were encountered during resolution
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of the \fIpath2\fP argument.
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.TP 7
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.B ENAMETOOLONG
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As a result of encountering a symbolic link in resolution of the \fIpath2\fP
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argument, the length of the substituted pathname
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string exceeded {PATH_MAX} bytes (including the terminating null byte),
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or the length of the string pointed to by \fIpath1\fP
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exceeded {SYMLINK_MAX}.
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.sp
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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Like a hard link, a symbolic link allows a file to have multiple logical
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names. The presence of a hard link guarantees the
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existence of a file, even after the original name has been removed.
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A symbolic link provides no such assurance; in fact, the file
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named by the \fIpath1\fP argument need not exist when the link is
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created. A symbolic link can cross file system boundaries.
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.LP
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Normal permission checks are made on each component of the symbolic
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link pathname during its resolution.
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.SH RATIONALE
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.LP
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Since IEEE\ Std\ 1003.1-2001 does not require any association of file
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times with symbolic links, there is no requirement
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that file times be updated by \fIsymlink\fP().
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIlchown\fP() , \fIlink\fP() , \fIlstat\fP() , \fIopen\fP() , \fIreadlink\fP()
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, \fIunlink\fP() ,
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the Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<unistd.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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