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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title>umask</title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><h4><a name = "tag_000_010_238"> </a>NAME</h4><blockquote>umask - set and get file mode creation mask</blockquote><h4><a name = "tag_000_010_239"> </a>SYNOPSIS</h4><blockquote><pre><code>#include <<a href="systypes.h.html">sys/types.h</a>>#include <<a href="sysstat.h.html">sys/stat.h</a>>mode_t umask(mode_t <i>cmask</i>);</code></pre></blockquote><h4><a name = "tag_000_010_240"> </a>DESCRIPTION</h4><blockquote>The<i>umask()</i>function sets the process' file mode creation mask to<i>cmask</i>and returns the previous value of the mask.Only the file permission bits of<i>cmask</i>(see<i><a href="sysstat.h.html"><sys/stat.h></a></i>)are used; the meaning of the other bits is implementation-dependent.<p>The process' file mode creation mask is used during<i><a href="open.html">open()</a></i>,<i><a href="creat.html">creat()</a></i>,<i><a href="mkdir.html">mkdir()</a></i>and<i><a href="mkfifo.html">mkfifo()</a></i>to turn off permission bits in the<i>mode</i>argument supplied.Bit positions that are set in<i>cmask</i>are cleared in the mode of the created file.</blockquote><h4><a name = "tag_000_010_241"> </a>RETURN VALUE</h4><blockquote>The file permission bits in the value returned by<i>umask()</i>will be the previous value of the file mode creation mask. The stateof any other bits in that value is unspecified, except that asubsequent call to<i>umask()</i>with the returned value as<i>cmask</i>will leave the state of the mask the same as its state beforethe first call, including any unspecified use of those bits.</blockquote><h4><a name = "tag_000_010_242"> </a>ERRORS</h4><blockquote>No errors are defined.</blockquote><h4><a name = "tag_000_010_243"> </a>EXAMPLES</h4><blockquote>None.</blockquote><h4><a name = "tag_000_010_244"> </a>APPLICATION USAGE</h4><blockquote>None.</blockquote><h4><a name = "tag_000_010_245"> </a>FUTURE DIRECTIONS</h4><blockquote>None.</blockquote><h4><a name = "tag_000_010_246"> </a>SEE ALSO</h4><blockquote><i><a href="creat.html">creat()</a></i>,<i><a href="mkdir.html">mkdir()</a></i>,<i><a href="mkfifo.html">mkfifo()</a></i>,<i><a href="open.html">open()</a></i>,<i><a href="sysstat.h.html"><sys/stat.h></a></i>,<i><a href="systypes.h.html"><sys/types.h></a></i>.</blockquote><h4>DERIVATION</h4><blockquote>Derived from Issue 1 of the SVID.</blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><hr size=2 noshade></body></html>⌨️ 快捷键说明
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