<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >is_writable</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PHP 手册" HREF="index.html"><LINK REL="UP" TITLE="Filesystem 文件系统函数" HREF="ref.filesystem.html"><LINK REL="PREVIOUS" TITLE="is_uploaded_file" HREF="function.is-uploaded-file.html"><LINK REL="NEXT" TITLE="is_writeable" HREF="function.is-writeable.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></HEAD ><BODY CLASS="refentry" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP 手册</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.is-uploaded-file.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.is-writeable.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.is-writable" ></A >is_writable</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN54124" ></A ><P > (PHP 4, PHP 5)</P >is_writable -- 判断给定的文件名是否可写</DIV ><DIV CLASS="refsect1" ><A NAME="AEN54127" ></A ><H2 >说明</H2 >bool <B CLASS="methodname" >is_writable</B > ( string filename )<BR ></BR ><P > 如果文件存在并且可写则返回 <TT CLASS="constant" ><B >TRUE</B ></TT >。<CODE CLASS="parameter" >filename</CODE > 参数可以是一个允许进行是否可写检查的目录名。 </P ><P > 记住 PHP 也许只能以运行 webserver 的用户名(通常为 'nobody')来访问文件。不计入安全模式的限制。 </P ><P > <TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN54140" ></A ><P ><B >例 1. <B CLASS="function" >is_writable()</B > 例子</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br />$filename </font><font color="#007700">= </font><font color="#DD0000">'test.txt'</font><font color="#007700">;<br />if (</font><font color="#0000BB">is_writable</font><font color="#007700">(</font><font color="#0000BB">$filename</font><font color="#007700">)) {<br /> echo </font><font color="#DD0000">'The file is writable'</font><font color="#007700">;<br />} else {<br /> echo </font><font color="#DD0000">'The file is not writable'</font><font color="#007700">;<br />}<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE > </P ><DIV CLASS="note" ><BLOCKQUOTE CLASS="note" ><P ><B >注意: </B >本函数的结果会被缓存。更多信息参见 <A HREF="function.clearstatcache.html" ><B CLASS="function" >clearstatcache()</B ></A >。</P ></BLOCKQUOTE ></DIV ><DIV CLASS="tip" ><BLOCKQUOTE CLASS="tip" ><P ><B >提示: </B >自 <TT CLASS="literal" >PHP 5.0.0</TT > 起本函数也可被<SPAN CLASS="emphasis" ><I CLASS="emphasis" >某些</I ></SPAN > URL wrapper 使用。参考<A HREF="wrappers.html" >附录 N</A > 来看哪些 wrapper 支持 <A HREF="function.stat.html" ><B CLASS="function" >stat()</B ></A > 系列函数的功能。</P ></BLOCKQUOTE ></DIV ><P > 参见 <A HREF="function.is-readable.html" ><B CLASS="function" >is_readable()</B ></A >,<A HREF="function.file-exists.html" ><B CLASS="function" >file_exists()</B ></A > 和 <A HREF="function.fwrite.html" ><B CLASS="function" >fwrite()</B ></A >。 </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.is-uploaded-file.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >起始页</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.is-writeable.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >is_uploaded_file</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.filesystem.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >is_writeable</TD ></TR ></TABLE ></DIV ></BODY ></HTML >