142 lines
5.2 KiB
HTML
142 lines
5.2 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<meta name="generator" content="HTML Tidy, see www.w3.org">
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 -->
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>umask</title>
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<body bgcolor="white">
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<basefont size="3"> <a name="umask"></a> <a name="tag_03_798"></a><!-- umask -->
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<!--header start-->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
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IEEE Std 1003.1-2001<br>
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Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<!--header end-->
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<hr size="2" noshade>
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<h4><a name="tag_03_798_01"></a>NAME</h4>
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<blockquote>umask - set and get the file mode creation mask</blockquote>
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<h4><a name="tag_03_798_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<p><code><tt>#include <<a href="../basedefs/sys/stat.h.html">sys/stat.h</a>><br>
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<br>
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mode_t umask(mode_t</tt> <i>cmask</i><tt>);<br>
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</tt></code></p>
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</blockquote>
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<h4><a name="tag_03_798_03"></a>DESCRIPTION</h4>
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<blockquote>
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<p>The <i>umask</i>() function shall set the process' file mode creation mask to <i>cmask</i> and return the previous value of the
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mask. Only the file permission bits of <i>cmask</i> (see <a href="../basedefs/sys/stat.h.html"><i><sys/stat.h></i></a>) are
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used; the meaning of the other bits is implementation-defined.</p>
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<p>The process' file mode creation mask is used during <a href="../functions/open.html"><i>open</i>()</a>, <a href=
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"../functions/creat.html"><i>creat</i>()</a>, <a href="../functions/mkdir.html"><i>mkdir</i>()</a>, and <a href=
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"../functions/mkfifo.html"><i>mkfifo</i>()</a> to turn off permission bits in the <i>mode</i> argument supplied. Bit positions that
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are set in <i>cmask</i> are cleared in the mode of the created file.</p>
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</blockquote>
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<h4><a name="tag_03_798_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>The file permission bits in the value returned by <i>umask</i>() shall be the previous value of the file mode creation mask. The
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state of any other bits in that value is unspecified, except that a subsequent call to <i>umask</i>() with the returned value as
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<i>cmask</i> shall leave the state of the mask the same as its state before the first call, including any unspecified use of those
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bits.</p>
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</blockquote>
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<h4><a name="tag_03_798_05"></a>ERRORS</h4>
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<blockquote>
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<p>No errors are defined.</p>
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</blockquote>
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<hr>
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<div class="box"><em>The following sections are informative.</em></div>
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<h4><a name="tag_03_798_06"></a>EXAMPLES</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_798_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_798_08"></a>RATIONALE</h4>
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<blockquote>
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<p>Unsigned argument and return types for <i>umask</i>() were proposed. The return type and the argument were both changed to
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<b>mode_t</b>.</p>
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<p>Historical implementations have made use of additional bits in <i>cmask</i> for their implementation-defined purposes. The
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addition of the text that the meaning of other bits of the field is implementation-defined permits these implementations to conform
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to this volume of IEEE Std 1003.1-2001.</p>
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</blockquote>
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<h4><a name="tag_03_798_09"></a>FUTURE DIRECTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_798_10"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="creat.html"><i>creat</i>()</a> , <a href="mkdir.html"><i>mkdir</i>()</a> , <a href="mkfifo.html"><i>mkfifo</i>()</a> ,
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<a href="open.html"><i>open</i>()</a> , the Base Definitions volume of IEEE Std 1003.1-2001, <a href=
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"../basedefs/sys/stat.h.html"><i><sys/stat.h></i></a>, <a href=
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"../basedefs/sys/types.h.html"><i><sys/types.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_798_11"></a>CHANGE HISTORY</h4>
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<blockquote>
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<p>First released in Issue 1. Derived from Issue 1 of the SVID.</p>
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</blockquote>
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<h4><a name="tag_03_798_12"></a>Issue 6</h4>
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<blockquote>
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<p>In the SYNOPSIS, the optional include of the <a href="../basedefs/sys/types.h.html"><i><sys/types.h></i></a> header is
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removed.<br>
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</p>
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<p>The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:</p>
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<ul>
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<li>
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<p>The requirement to include <a href="../basedefs/sys/types.h.html"><i><sys/types.h></i></a> has been removed. Although <a
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href="../basedefs/sys/types.h.html"><i><sys/types.h></i></a> was required for conforming implementations of previous POSIX
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specifications, it was not required for UNIX applications.</p>
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</li>
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</ul>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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<center><font size="2"><!--footer start-->
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UNIX ® is a registered Trademark of The Open Group.<br>
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POSIX ® is a registered Trademark of The IEEE.<br>
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