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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2004 IEEE and The Open Group, All Rights Reserved --><title>mprotect</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="mprotect"></a> <a name="tag_03_381"></a><!-- mprotect --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2004 Edition<br>Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_381_01"></a>NAME</h4><blockquote>mprotect - set protection of memory mapping</blockquote><h4><a name="tag_03_381_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><div class="box"><code><tt><sup>[<a href="javascript:open_code('MPR')">MPR</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> #include <<a href="../basedefs/sys/mman.h.html">sys/mman.h</a>><br><br> int mprotect(void *</tt><i>addr</i><tt>, size_t</tt> <i>len</i><tt>, int</tt> <i>prot</i><tt>); <img src="../images/opt-end.gif"alt="[Option End]" border="0"></tt></code></div><tt><br></tt></blockquote><h4><a name="tag_03_381_03"></a>DESCRIPTION</h4><blockquote><p>The <i>mprotect</i>() function shall change the access protections to be that specified by <i>prot</i> for those whole pagescontaining any part of the address space of the process starting at address <i>addr</i> and continuing for <i>len</i> bytes. Theparameter <i>prot</i> determines whether read, write, execute, or some combination of accesses are permitted to the data beingmapped. The <i>prot</i> argument should be either PROT_NONE or the bitwise-inclusive OR of one or more of PROT_READ, PROT_WRITE,and PROT_EXEC.</p><p>If an implementation cannot support the combination of access types specified by <i>prot</i>, the call to <i>mprotect</i>()shall fail.</p><p>An implementation may permit accesses other than those specified by <i>prot</i>; however, no implementation shall permit a writeto succeed where PROT_WRITE has not been set or shall permit any access where PROT_NONE alone has been set. Implementations shallsupport at least the following values of <i>prot</i>: PROT_NONE, PROT_READ, PROT_WRITE, and the bitwise-inclusive OR of PROT_READand PROT_WRITE. If PROT_WRITE is specified, the application shall ensure that it has opened the mapped objects in the specifiedaddress range with write permission, unless MAP_PRIVATE was specified in the original mapping, regardless of whether the filedescriptors used to map the objects have since been closed.</p><p>The implementation shall require that <i>addr</i> be a multiple of the page size as returned by <a href="../functions/sysconf.html"><i>sysconf</i>()</a>.</p><p>The behavior of this function is unspecified if the mapping was not established by a call to <a href="../functions/mmap.html"><i>mmap</i>()</a>.</p><p>When <i>mprotect</i>() fails for reasons other than [EINVAL], the protections on some of the pages in the range[<i>addr</i>,<i>addr</i>+<i>len</i>) may have been changed.</p></blockquote><h4><a name="tag_03_381_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion, <i>mprotect</i>() shall return 0; otherwise, it shall return -1 and set <i>errno</i> to indicate theerror.</p></blockquote><h4><a name="tag_03_381_05"></a>ERRORS</h4><blockquote><p>The <i>mprotect</i>() function shall fail if:</p><dl compact><dt>[EACCES]</dt><dd>The <i>prot</i> argument specifies a protection that violates the access permission the process has to the underlying memoryobject.</dd><dt>[EAGAIN]</dt><dd>The <i>prot</i> argument specifies PROT_WRITE over a MAP_PRIVATE mapping and there are insufficient memory resources to reservefor locking the private page.</dd><dt>[EINVAL]</dt><dd>The <i>addr</i> argument is not a multiple of the page size as returned by <a href="../functions/sysconf.html"><i>sysconf</i>()</a>.</dd><dt>[ENOMEM]</dt><dd>Addresses in the range [<i>addr</i>,<i>addr</i>+<i>len</i>) are invalid for the address space of a process, or specify one ormore pages which are not mapped.</dd><dt>[ENOMEM]</dt><dd>The <i>prot</i> argument specifies PROT_WRITE on a MAP_PRIVATE mapping, and it would require more space than the system is ableto supply for locking the private pages, if required.</dd><dt>[ENOTSUP]</dt><dd>The implementation does not support the combination of accesses requested in the <i>prot</i> argument.</dd></dl></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_381_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_381_07"></a>APPLICATION USAGE</h4><blockquote><p>The [EINVAL] error above is marked EX because it is defined as an optional error in the POSIX Realtime Extension.</p></blockquote><h4><a name="tag_03_381_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_381_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_381_10"></a>SEE ALSO</h4><blockquote><p><a href="mmap.html"><i>mmap</i>()</a>, <a href="sysconf.html"><i>sysconf</i>()</a>, the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/sys/mman.h.html"><i><sys/mman.h></i></a></p></blockquote><h4><a name="tag_03_381_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 4, Version 2.</p></blockquote><h4><a name="tag_03_381_12"></a>Issue 5</h4><blockquote><p>Moved from X/OPEN UNIX extension to BASE.</p><p>Aligned with <i>mprotect</i>() in the POSIX Realtime Extension as follows:</p><ul><li><p>The DESCRIPTION is largely reworded.</p></li><li><p>[ENOTSUP] and a second form of [ENOMEM] are added as mandatory error conditions.</p></li><li><p>[EAGAIN] is moved from the optional to the mandatory error conditions.</p></li></ul></blockquote><h4><a name="tag_03_381_13"></a>Issue 6</h4><blockquote><p>The <i>mprotect</i>() function is marked as part of the Memory Protection option.</p><p>The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:</p><ul><li><p>The DESCRIPTION is updated to state that implementations require <i>addr</i> to be a multiple of the page size as returned by <ahref="../functions/sysconf.html"><i>sysconf</i>()</a>.</p></li><li><p>The [EINVAL] error condition is added.</p></li></ul><p>The DESCRIPTION is updated to avoid use of the term "must" for application requirements.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>⌨️ 快捷键说明
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