📄 malloc.html
字号:
<!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) 2001-2003 The Open Group, All Rights Reserved --><title>malloc</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="malloc"></a> <a name="tag_03_357"></a><!-- malloc --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2003 Edition<br>Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_357_01"></a>NAME</h4><blockquote>malloc - a memory allocator</blockquote><h4><a name="tag_03_357_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><p><code><tt>#include <<a href="../basedefs/stdlib.h.html">stdlib.h</a>><br><br> void *malloc(size_t</tt> <i>size</i><tt>);<br></tt></code></p></blockquote><h4><a name="tag_03_357_03"></a>DESCRIPTION</h4><blockquote><div class="box"><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]"border="0"> The functionality described on this reference page is aligned with the ISO C standard. Any conflict between therequirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers tothe ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></div><p>The <i>malloc</i>() function shall allocate unused space for an object whose size in bytes is specified by <i>size</i> and whosevalue is unspecified.</p><p>The order and contiguity of storage allocated by successive calls to <i>malloc</i>() is unspecified. The pointer returned if theallocation succeeds shall be suitably aligned so that it may be assigned to a pointer to any type of object and then used to accesssuch an object in the space allocated (until the space is explicitly freed or reallocated). Each such allocation shall yield apointer to an object disjoint from any other object. The pointer returned points to the start (lowest byte address) of theallocated space. If the space cannot be allocated, a null pointer shall be returned. If the size of the space requested is 0, thebehavior is implementation-defined: the value returned shall be either a null pointer or a unique pointer.</p></blockquote><h4><a name="tag_03_357_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion with <i>size</i> not equal to 0, <i>malloc</i>() shall return a pointer to the allocated space. If<i>size</i> is 0, either a null pointer or a unique pointer that can be successfully passed to <a href="../functions/free.html"><i>free</i>()</a> shall be returned. Otherwise, it shall return a null pointer <sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> and set<i>errno</i> to indicate the error. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p></blockquote><h4><a name="tag_03_357_05"></a>ERRORS</h4><blockquote><p>The <i>malloc</i>() function shall fail if:</p><dl compact><dt>[ENOMEM]</dt><dd><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">Insufficient storage space is available. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd></dl></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_357_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_357_07"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_357_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_357_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_357_10"></a>SEE ALSO</h4><blockquote><p><a href="calloc.html"><i>calloc</i>()</a> , <a href="free.html"><i>free</i>()</a> , <a href="realloc.html"><i>realloc</i>()</a>, the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/stdlib.h.html"><i><stdlib.h></i></a></p></blockquote><h4><a name="tag_03_357_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 1. Derived from Issue 1 of the SVID.</p></blockquote><h4><a name="tag_03_357_12"></a>Issue 6</h4><blockquote><p>Extensions beyond the ISO C standard are marked.</p><p>The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:</p><ul><li><p>In the RETURN VALUE section, the requirement to set <i>errno</i> to indicate an error is added.</p></li><li><p>The [ENOMEM] error condition is added.</p></li></ul></blockquote><div class="box"><em>End of informative text.</em></div><hr><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
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -