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21 KiB
HTML
850 lines
21 KiB
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
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<title>faccessx()--Determine File Accessibility for a Class of Users</title>
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<!-- Begin Header Records ========================================== -->
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<!-- file cleaned -->
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<!-- Change History: -->
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<!-- 010314 JKUGEL: Creation based on access.htm, V5R2, DCR 98686 -->
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<!-- 011022 JTROUS Changes from API Review 1, V5R2 -->
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<!-- 011025 JKUGEL: Changes for ptr 9955545 -->
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<!-- 020227 JTROUS Minor addition per Marcus Lundberg comment, v5r2-->
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<!-- 020618 EMIG Updates for NFS threadsafety, V5R3 -->
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<!-- 020514 JET: This file has undergone html cleanup -->
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<!-- 020718 MFENLON: updated for QFileSvr.400 threadsafety, V5R3 -->
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<!-- 040721 JTROUS: fix OS/400 reference, no change flag, V5R4 -->
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<!-- 050323 JTROUS: fix enums, no change flag, V5R4 -->
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<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</head>
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<body>
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<!-- End Header Records --><!--Java sync-link-->
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<script language="Javascript" src="../rzahg/synch.js" type="text/javascript">
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</script>
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<a name="Top_Of_Page"></a>
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<h2>faccessx()--Determine File Accessibility for a Class of Users</h2>
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<div class="box" style="width: 70%;">
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<br>
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Syntax<br>
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<pre>
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#include <unistd.h>
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int faccessx(int <em>fildes</em>, int <em>amode</em>, int <em>who</em>);
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</pre>
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Service Program Name: QP0LLIB1<br>
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<!-- iddvc RMBR -->
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<br>
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Default Public Authority: *USE<br>
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<!-- iddvc RMBR -->
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<br>
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Threadsafe: Conditional; see <a href="#USAGE_NOTES">Usage Notes</a>.<br>
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<!-- iddvc RMBR -->
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<br>
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</div>
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<p>The <strong>faccessx()</strong> function determines whether a file can be
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accessed by a specified class of users in a particular manner.</p>
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<p>Adopted authority is not used.</p>
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<br>
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<h3>Parameters</h3>
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<dl>
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<dt><strong><em>fildes</em></strong></dt>
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<dd>(Input) The file descriptor of the file that is having its accessibility
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checked.<br>
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<br>
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</dd>
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<dt><strong><em>amode</em></strong></dt>
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<dd>(Input) A bitwise representation of the access permissions to be
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checked.<br>
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<br>
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<p>The following symbols, which are defined in the
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<<strong>unistd.h</strong>> header file, can be used in <em>
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amode</em>:</p>
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<dl compact>
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<dt><em><samp>F_OK</samp></em></dt>
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<dd>(<em>x'00'</em>) Tests whether the file exists</dd>
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<dt><em><samp>R_OK</samp></em></dt>
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<dd>(<samp>x'04'</samp>) Tests whether the file can be accessed for
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reading</dd>
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<dt><em><samp>W_OK</samp></em></dt>
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<dd>(<em>x'02'</em>) Tests whether the file can be accessed for writing</dd>
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<dt><em><samp>X_OK</samp></em></dt>
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<dd>(<em>x'01'</em>) Tests whether the file can be accessed for execution</dd>
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</dl>
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<p>You can take the bitwise inclusive OR of any or all of the last three
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symbols to test several access modes at once. If you are using F_OK to test for
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the existence of the file, you cannot use OR with any of the other symbols. If
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any other bits are set in <em>amode</em>, <strong>faccessx()</strong> returns
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the [EINVAL] error.</p>
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<br>
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</dd>
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<dt><strong><em>who</em></strong></dt>
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<dd>(Input) The class of users whose authority is to be checked.
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<p>The following symbols, which are defined in the
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<<strong>unistd.h</strong>> header file, can be used in <em>who</em>:</p>
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<dl compact>
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<dt><em><samp>ACC_SELF</samp></em></dt>
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<dd>(<em>x'00'</em>) Determines if specified access is permitted for the
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current thread. The effective user and group IDs are used.
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<p><strong>Note:</strong> If the real and effective user ID are the same and
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the real and effective group ID are the same, the request is treated as
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ACC_INVOKER. See the Usage Notes for more details.</p>
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</dd>
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<dt><em><samp>ACC_INVOKER</samp></em></dt>
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<dd>(<em>x'01'</em>) Determines if specified access is permitted for the
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current thread. The effective user and group IDs are used.</dd>
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<dd><br>
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<br>
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</dd>
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<dt><em><samp>ACC_OTHERS</samp></em></dt>
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<dd>(<em>x'08'</em>) Determines if specified access is permitted for any user
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other than the object owner. Only one of <em>R_OK</em>, <em>W_OK</em>, and <em>
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X_OK</em> is permitted when <strong>who</strong> is <em>ACC_OTHERS</em>.
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Privileged users (users with *ALLOBJ special authority) are not considered in
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this check.</dd>
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<dd><br>
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<br>
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</dd>
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<dt><em><samp>ACC_ALL</samp></em></dt>
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<dd>(<em>x'20'</em>) Determines if specified access is permitted for all users.
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Only one of <em>R_OK</em>, <em>W_OK</em>, and <em>X_OK</em> is permitted when
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<strong>who</strong> is <em>ACC_ALL</em>. Privileged users (users with *ALLOBJ
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special authority) are not considered in this check.</dd>
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</dl>
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</dd>
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</dl>
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<br>
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<h3>Authorities</h3>
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<p>The following authorities are required if the <strong>who</strong> parameter
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is <em>ACC_SELF</em> or <em>ACC_INVOKER</em>. If <em>ACC_SELF</em> is
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specified, the effective UID and GID of the caller are used. If <em>
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ACC_INVOKER</em> is used, the real UID and GID of the caller are used.</p>
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<p><strong><a name="TBLFACCESSX">Authorization Required for
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faccessx()</a></strong></p>
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<table border width="100%" cellpadding="5">
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<!-- cols="60 20 20" -->
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<tr>
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<th align="left" valign="bottom">Object Referred to</th>
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<th align="left" valign="bottom">Authority Required</th>
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<th align="left" valign="bottom">errno</th>
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</tr>
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<tr>
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<td align="left" valign="top" width="90%">Object when R_OK is specified</td>
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<td align="left" valign="top" width="5%">*R</td>
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<td align="left" valign="top" width="5%">EACCES</td>
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</tr>
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<tr>
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<td align="left" valign="top">Object when W_OK is specified</td>
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<td align="left" valign="top">*W</td>
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<td align="left" valign="top">EACCES</td>
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</tr>
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<tr>
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<td align="left" valign="top">Object when X_OK is specified</td>
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<td align="left" valign="top">*X</td>
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<td align="left" valign="top">EACCES</td>
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</tr>
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<tr>
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<td align="left" valign="top">Object when R_OK | W_OK is
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specified</td>
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<td align="left" valign="top">*RW</td>
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<td align="left" valign="top">EACCES</td>
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</tr>
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<tr>
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<td align="left" valign="top">Object when R_OK | X_OK is
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specified</td>
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<td align="left" valign="top">*RX</td>
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<td align="left" valign="top">EACCES</td>
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</tr>
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<tr>
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<td align="left" valign="top">Object when W_OK | X_OK is
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specified</td>
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<td align="left" valign="top">*WX</td>
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<td align="left" valign="top">EACCES</td>
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</tr>
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<tr>
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<td align="left" valign="top">Object when R_OK | W_OK | X_OK is
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specified</td>
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<td align="left" valign="top">*RWX</td>
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<td align="left" valign="top">EACCES</td>
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</tr>
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<tr>
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<td align="left" valign="top">Object when F_OK is specified</td>
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<td align="left" valign="top">None</td>
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<td align="left" valign="top">None</td>
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</tr>
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</table>
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<p>If the current thread has *ALLOBJ special authority, <strong>
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faccessx()</strong> with <em>ACC_SELF</em> or <em>ACC_INVOKER</em> will
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indicate success for R_OK, W_OK, or X_OK even if none of the permission bits
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are set.</p>
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<br>
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<h3>Return Value</h3>
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<dl compact>
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<dt><em>0</em></dt>
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<dd><strong>faccessx()</strong> was successful.</dd>
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<dt><em>-1</em></dt>
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<dd><strong>faccessx()</strong> was not successful (or the specified access is
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not permitted for the class of users being checked). The <em>errno</em> global
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variable is set to indicate the error.</dd>
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</dl>
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<br>
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<h3>Error Conditions</h3>
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<p>If <strong>faccessx()</strong> is not successful, <em>errno</em> usually
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indicates one of the following errors. Under some conditions, <em>errno</em>
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could indicate an error other than those listed here.</p>
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<table cellpadding="5">
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<!-- cols="25 75" -->
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<tr>
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<th align="left" valign="bottom">Error condition</th>
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<th align="left" valign="bottom">Additional information</th>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EACCES">EACCES</a>]</em></td>
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<td align="left" valign="top">
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<p>The class of users specified by the <em>who</em> parameter does not have the
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permission indicated by the <em>amode</em> parameter.</p>
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<p>If you are accessing a remote file through the Network File System, update
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operations to file permissions at the server are not reflected at the client
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until updates to data that is stored locally by the Network File System take
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place. (Several options on the Add Mounted File System (ADDMFS) command
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determine the time between refresh operations of local data.) Access to a
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remote file may also fail due to different mappings of user IDs (UID) or group
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IDs (GID) on the local and remote systems.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EAGAIN">EAGAIN</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EBADFID">EBADFID</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EBADNAME">EBADNAME</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EBUSY">EBUSY</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#ECONVERT">ECONVERT</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EDAMAGE">EDAMAGE</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EFAULT">EFAULT</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EFILECVT">EFILECVT</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EINVAL">EINVAL</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EIO">EIO</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EINTR">EINTR</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#ENOSPC">ENOSPC</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#ENOTAVAIL">ENOTAVAIL</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#ENOTSAFE">ENOTSAFE</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#ENOTSUP">ENOTSUP</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>[<a href="unix14.htm#EROOBJ">EROOBJ</a>]</em></td>
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<td align="left" valign="top">
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</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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||
|
<em>[<a href="unix14.htm#ESTALE">ESTALE</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
<p>If you are accessing a remote file through the Network File System, the file
|
||
|
may have been deleted at the server.</p>
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#ETXTBSY">ETXTBSY</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#EUNKNOWN">EUNKNOWN</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
</table>
|
||
|
|
||
|
<p>If interaction with a file server is required to access the object, <em>
|
||
|
errno</em> could indicate one of the following errors:</p>
|
||
|
|
||
|
<table cellpadding="5">
|
||
|
<!-- cols="25 75" -->
|
||
|
|
||
|
<tr>
|
||
|
<th align="left" valign="bottom">Error condition</th>
|
||
|
<th align="left" valign="bottom">Additional information</th>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#EADDRNOTAVAIL">EADDRNOTAVAIL</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#ECONNABORTED">ECONNABORTED</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#ECONNREFUSED">ECONNREFUSED</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#ECONNRESET">ECONNRESET</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#EHOSTDOWN">EHOSTDOWN</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#EHOSTUNREACH">EHOSTUNREACH</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#ENETDOWN">ENETDOWN</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#ENETRESET">ENETRESET</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#ENETUNREACH">ENETUNREACH</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#ESTALE">ESTALE</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
<p>If you are accessing a remote file through the Network File System, the file
|
||
|
may have been deleted at the server.</p>
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#ETIMEDOUT">ETIMEDOUT</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td align="left" valign="top">
|
||
|
<em>[<a href="unix14.htm#EUNATCH">EUNATCH</a>]</em></td>
|
||
|
|
||
|
<td align="left" valign="top">
|
||
|
|
||
|
</td>
|
||
|
</tr>
|
||
|
</table>
|
||
|
|
||
|
<br>
|
||
|
<br>
|
||
|
<h3>Error Messages</h3>
|
||
|
|
||
|
<p>The following messages may be sent from this function:</p>
|
||
|
|
||
|
<table width="100%">
|
||
|
<tr>
|
||
|
<th align="left" valign="top">Message ID</th>
|
||
|
<th align="left" valign="top">Error Message Text</th>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td width="15%" valign="top">CPE3418 E</td>
|
||
|
<td width="85%" valign="top">Possible APAR condition or hardware failure.</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td valign="top">CPFA0D4 E</td>
|
||
|
<td valign="top">File system error occurred. Error number &1.</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td valign="top">CPF3CF2 E</td>
|
||
|
<td valign="top">Error(s) occurred during running of &1 API.</td>
|
||
|
</tr>
|
||
|
|
||
|
<tr>
|
||
|
<td valign="top">CPF9872 E</td>
|
||
|
<td valign="top">Program or service program &1 in library &2 ended.
|
||
|
Reason code &3.</td>
|
||
|
</tr>
|
||
|
</table>
|
||
|
|
||
|
<br>
|
||
|
<br>
|
||
|
<h3><a name="usage_notes">Usage Notes</a></h3>
|
||
|
|
||
|
<ol type="1">
|
||
|
<li>This function will fail with error code [ENOTSAFE] when both of the
|
||
|
following conditions occur:
|
||
|
|
||
|
<ul>
|
||
|
<li>Where multiple threads exist in the job.<br>
|
||
|
</li>
|
||
|
|
||
|
<li>The object this function is operating on resides in a file system that is
|
||
|
not threadsafe. Only the following file systems are threadsafe for this
|
||
|
function:
|
||
|
|
||
|
<ul>
|
||
|
<li>"Root" (/)</li>
|
||
|
|
||
|
<li>QOpenSys</li>
|
||
|
|
||
|
<li>User-defined</li>
|
||
|
|
||
|
<li>QNTC</li>
|
||
|
|
||
|
<li>QSYS.LIB</li>
|
||
|
|
||
|
<li>Independent ASP QSYS.LIB</li>
|
||
|
|
||
|
<li>QOPT</li>
|
||
|
|
||
|
<li>Network File System</li>
|
||
|
|
||
|
|
||
|
<li>QFileSvr.400</li>
|
||
|
|
||
|
</ul>
|
||
|
</li>
|
||
|
</ul>
|
||
|
|
||
|
<br>
|
||
|
</li>
|
||
|
|
||
|
<li>ACC_SELF Mapped to ACC_INVOKER
|
||
|
|
||
|
<p>Some physical file systems do not support <em>ACC_SELF</em> for the <em>
|
||
|
who</em> parameter. However, <strong>faccessx()</strong> will change the <em>
|
||
|
who</em> parameter from <em>ACC_SELF</em> to <em>ACC_INVOKER</em> if the
|
||
|
caller's real and effective user ID are equal, and the caller's real and
|
||
|
effective group ID are equal.</p>
|
||
|
|
||
|
<br>
|
||
|
</li>
|
||
|
|
||
|
<li>Network File System Differences
|
||
|
|
||
|
<p>The Network File System will only support the value <em>ACC_INVOKER</em> for
|
||
|
the <em>who</em> parameter. If <strong>faccessx()</strong> is called on a file
|
||
|
in a mounted Network File System directory with a value for <em>who</em> other
|
||
|
than <em>ACC_INVOKER</em>, the call will return -1 and errno ENOTSUP. <strong>
|
||
|
Note:</strong> If the value for <em>who</em> has been mapped from <em>
|
||
|
ACC_SELF</em> to <em>ACC_INVOKER</em> as previously described, then ENOTSUP
|
||
|
will not be returned.</p>
|
||
|
|
||
|
<p>Local access to remote files through the Network File System may produce
|
||
|
unexpected results due to conditions at the server. Once a file is open,
|
||
|
subsequent requests to perform operations on the file can fail because file
|
||
|
attributes are checked at the server on each request. If permissions on the
|
||
|
file are made more restrictive at the server or the file is unlinked or made
|
||
|
unavailable by the server for another client, your operation on an open file
|
||
|
descriptor will fail when the local Network File System receives these updates.
|
||
|
The local Network File System also impacts operations that retrieve file
|
||
|
attributes. Recent changes at the server may not be available at your client
|
||
|
yet, and old values may be returned from operations. (Several options on the
|
||
|
Add Mounted File System (ADDMFS) command determine the time between refresh
|
||
|
operations of local data.)</p>
|
||
|
|
||
|
<br>
|
||
|
</li>
|
||
|
|
||
|
<li>QNTC File System Differences
|
||
|
|
||
|
<p>The QNTC File System will only support the value <em>ACC_INVOKER</em> for
|
||
|
the <em>who</em> parameter. If <strong>faccessx()</strong> is called on a file
|
||
|
in the QNTC File System with a value for <em>who</em> other than <em>
|
||
|
ACC_INVOKER</em>, the call will return -1 and errno ENOTSUP.</p>
|
||
|
<p><strong>
|
||
|
Note:</strong> If the value for <em>who</em> has been mapped from <em>
|
||
|
ACC_SELF</em> to <em>ACC_INVOKER</em> as previously described, then ENOTSUP
|
||
|
will not be returned.</p>
|
||
|
|
||
|
<br>
|
||
|
</li>
|
||
|
|
||
|
<li>QOPT File System Differences
|
||
|
|
||
|
<p>If the file descriptor refers to an object that exists on a volume formatted
|
||
|
in Universal Disk Format (UDF), the authorization that is checked for the
|
||
|
object follows the rules described in the previous table,
|
||
|
<a href="#TBLFACCESSX">Authorization Required for faccessx()</a>. If the
|
||
|
object exists on a volume formatted in some other media format, no
|
||
|
authorization checks are made on the object. The volume authorization list is
|
||
|
checked for the requested authority regardless of the volume media format.</p>
|
||
|
|
||
|
<br>
|
||
|
</li>
|
||
|
|
||
|
<li>QFileSvr.400 File System Differences<br>
|
||
|
<br>
|
||
|
|
||
|
|
||
|
<p>The QFileSvr.400 File System will only support the value <em>
|
||
|
ACC_INVOKER</em> for the <em>who</em> parameter. If <strong>faccessx()</strong>
|
||
|
is called on a file in the QFileSvr.400 File System with a value for <em>
|
||
|
who</em> other than <em>ACC_INVOKER</em>, the call will return -1 and errno
|
||
|
ENOTSUP. </p>
|
||
|
<p><strong>Note:</strong> If the value for <em>who</em> has been mapped
|
||
|
from <em>ACC_SELF</em> to <em>ACC_INVOKER</em> as previously described, then
|
||
|
ENOTSUP will not be returned.</p>
|
||
|
|
||
|
<br>
|
||
|
</li>
|
||
|
|
||
|
<li>QNetWare File System Differences<br>
|
||
|
<br>
|
||
|
|
||
|
|
||
|
<p>The QNetWare File System will only support the value <em>ACC_INVOKER</em>
|
||
|
for the <em>who</em> parameter. If <strong>faccessx()</strong> is called on a
|
||
|
file in the QNetWare File System with a value for <em>who</em> other than <em>
|
||
|
ACC_INVOKER</em>, the call will return -1 and errno ENOTSUP.</p>
|
||
|
<p> <strong>
|
||
|
Note:</strong> If the value for <em>who</em> has been mapped from <em>
|
||
|
ACC_SELF</em> to <em>ACC_INVOKER</em> as previously described, then ENOTSUP
|
||
|
will not be returned.</p>
|
||
|
</li>
|
||
|
</ol>
|
||
|
|
||
|
<br>
|
||
|
<h3>Related Information</h3>
|
||
|
|
||
|
<ul>
|
||
|
<li>The <<strong>unistd.h</strong>> file (see <a href="unix13.htm">Header
|
||
|
Files for UNIX-Type Functions</a>)
|
||
|
</li>
|
||
|
|
||
|
<li>The <<strong>limits.h</strong>> file (see <a href="unix13.htm">Header
|
||
|
Files for UNIX-Type Functions</a>)
|
||
|
</li>
|
||
|
|
||
|
<li><a href="chmod.htm">chmod()</a>--Change File Authorizations
|
||
|
</li>
|
||
|
|
||
|
<li><a href="open.htm">open()</a>--Open File
|
||
|
</li>
|
||
|
|
||
|
<li><a href="access.htm">access()</a>--Determine File Accessibility
|
||
|
</li>
|
||
|
|
||
|
<li><a href="accessx.htm">accessx()</a>--Determine File Accessibility for a
|
||
|
Class of Users
|
||
|
</li>
|
||
|
|
||
|
<li><a href="accessxu.htm">QlgAccessx()</a>--Determine File Accessibility for a
|
||
|
Class of Users (using NLS-enabled path name)
|
||
|
</li>
|
||
|
|
||
|
<li><a href="accessu.htm">QlgAccess()</a>--Determine File Accessibility (using
|
||
|
NLS-enabled path name)
|
||
|
</li>
|
||
|
|
||
|
<li><a href="stat.htm">stat()</a>--Get File Information
|
||
|
</li>
|
||
|
</ul>
|
||
|
|
||
|
<br>
|
||
|
<h3>Example</h3>
|
||
|
|
||
|
<p>See <a href="../apiref/aboutapis.htm#codedisclaimer">Code disclaimer information</a>
|
||
|
for information pertaining to code examples.</p>
|
||
|
|
||
|
<p>The following example determines how a file is accessed:</p>
|
||
|
|
||
|
<pre>
|
||
|
#include <stdio.h>
|
||
|
#include <unistd.h>
|
||
|
#include <fcntl.h>
|
||
|
|
||
|
main() {
|
||
|
char path[]="/myfile";
|
||
|
int fd;
|
||
|
|
||
|
fd = open(path, O_RDONLY);
|
||
|
if (fd == -1)
|
||
|
{
|
||
|
printf("Error opening file.\n");
|
||
|
return;
|
||
|
}
|
||
|
|
||
|
if (faccessx(fd, R_OK, ACC_OTHERS) == 0)
|
||
|
printf("Someone besides the owner has read access to '%s'\n", path);
|
||
|
if (faccessx(fd, W_OK, ACC_OTHERS) == 0)
|
||
|
printf("Someone besides the owner has write access to '%s'\n", path);
|
||
|
if (faccessx(fd, X_OK, ACC_OTHERS) == 0)
|
||
|
printf("Someone besides the owner has search access to '%s'\n", path);
|
||
|
close(fd);
|
||
|
}
|
||
|
</pre>
|
||
|
|
||
|
<p><strong>Output:</strong></p>
|
||
|
|
||
|
<p>In this example <strong>faccessx()</strong> was called on a descriptor for
|
||
|
'/myfile'. The following would be the output if someone other than the owner
|
||
|
has *R authority, someone besides the owner has *W authority, and noone other
|
||
|
than the owner has *X authority.</p>
|
||
|
|
||
|
<br>
|
||
|
<pre>
|
||
|
Someone besides the owner has read access to '/'
|
||
|
Someone besides the owner has write access to '/'
|
||
|
</pre>
|
||
|
|
||
|
<br>
|
||
|
<hr>
|
||
|
API introduced: V5R2
|
||
|
|
||
|
<hr>
|
||
|
<center>
|
||
|
<table cellpadding="2" cellspacing="2">
|
||
|
<tr align="center">
|
||
|
<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> | <a href=
|
||
|
"unix.htm">UNIX-Type APIs</a> | <a href="aplist.htm">APIs by category</a></td>
|
||
|
</tr>
|
||
|
</table>
|
||
|
</center>
|
||
|
</body>
|
||
|
</html>
|
||
|
|