os161 / man / syscall / link.html
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<html>
<head>
<title>link</title>
<body bgcolor=#ffffff>
<h2 align=center>link</h2>
<h4 align=center>OS/161 Reference Manual</h4>

<h3>Name</h3>
<p>
link - create hard link to a file
</p>

<h3>Library</h3>
<p>
Standard C Library (libc, -lc)
</p>

<h3>Synopsis</h3>
<p>
<tt>#include &lt;unistd.h&gt;</tt><br>
<br>
<tt>int</tt><br>
<tt>link(const char *</tt><em>oldname</em><tt>,
const char *</tt><em>newname</em><tt>);</tt>
</p>

<h3>Description</h3>
<p>
<tt>link</tt> creates a new name, <em>newname</em>, for the file
referred to by <em>oldname</em>. Henceforth, both names are equally
valid ways to refer to the same file. The file is only deleted when
all names are removed. This is a "hard link".
</p>

<p>
The creation of the new name is atomic. The two names must be on the
same filesystem. Directories may not be hard-linked.
</p>

<h3>Return Values</h3>
<p>
On success, <tt>link</tt> returns 0. On error, -1 is returned, and <A
HREF=errno.html>errno</A> is set according to the error encountered.
</p>

<h3>Errors</h3>
<p>
The following error codes should be returned under the conditions
given. Other error codes may be returned for other cases not
mentioned here.

<table width=90%>
<tr><td width=5% rowspan=11>&nbsp;</td>
    <td width=10% valign=top>ENODEV</td>
				<td>The device prefix of one of the names did
				not exist.</td></tr>
<tr><td valign=top>ENOTDIR</td>	<td>A non-final component of one of the names
				was not a directory.</td></tr>
<tr><td valign=top>ENOENT</td>	<td>A non-final component of <em>newname</em>
				did not exist.</td></tr>
<tr><td valign=top>ENOENT</td>	<td><em>oldname</em> does not exist.</td></tr>
<tr><td valign=top>EEXIST</td>	<td><em>newname</em> already exists.</td></tr>
<tr><td valign=top>EISDIR</td>	<td><em>oldname</em> is a directory.</td></tr>
<tr><td valign=top>EXDEV</td>	<td>The two names are on different
				filesystems.</td></tr>
<tr><td valign=top>EMLINK</td>	<td>There are already too many links to
				<em>oldname</em>.</td></tr>
<tr><td valign=top>ENOSPC</td>	<td>The filesystem involved is full.</td></tr>
<tr><td valign=top>EIO</td>	<td>A hard I/O error occurred.</td></tr>
<tr><td valign=top>EFAULT</td>	<td>One of the arguments was an
				invalid pointer.</td></tr>
</table>
</p>

</body>
</html>