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<html><head><title>POSIX (Perl in a Nutshell, 2nd Edition)</title><link rel="stylesheet" type="text/css" href="../style/style1.css" /><meta name="DC.Creator" content="Stephen Spainhour" /><meta name="DC.Format" content="text/xml" scheme="MIME" /><meta name="DC.Language" content="en-US" /><meta name="DC.Publisher" content="O'Reilly & Associates, Inc." /><meta name="DC.Source" scheme="ISBN" content="0596002416L" /><meta name="DC.Subject.Keyword" content="stuff" /><meta name="DC.Title" content="Perl in a Nutshell, 2nd Edition" /><meta name="DC.Type" content="Text.Monograph" /></head><body bgcolor="#ffffff"><img src="gifs/smbanner.gif" usemap="#banner-map" border="0" alt="Book Home" /><map name="banner-map"><area shape="rect" coords="1,-2,616,66" href="index.htm" alt="Java and XSLT" /><area shape="rect" coords="629,-11,726,25" href="jobjects/fsearch.htm" alt="Search this book" /></map><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch08_176.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0" /></a></td><td align="center" valign="top" width="228" /><td align="right" valign="top" width="228"><a href="ch08_178.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0" /></a></td></tr></table></div><h2 class="sect1">8.177. POSIX</h2><p><a name="INDEX-1539" />Provides accessto standard POSIX 1003.1 identifiers: functions, classes, andconstants. Can be <tt class="literal">use</tt> d to import one or multiplesymbols:</p><blockquote><pre class="code">use POSIX; # Import all symbolsuse POSIX qw(setsid); # Import one symboluse POSIX qw(:errno_h :fcntl_h); # Import sets of symbols</pre></blockquote><p>Functions listed as C-specific are not implemented.</p><a name="ch08-517-fm2xml" /><table border="1" cellpadding="3"><tr><th><p>Function</p></th><th><p>Description</p></th></tr><tr><td><p><tt class="literal">_exit</tt></p></td><td><p>Identical to C function <tt class="literal">_exit(2)</tt></p></td></tr><tr><td><p><tt class="literal">abort</tt></p></td><td><p>Identical to C function <tt class="literal">abort(3)</tt></p></td></tr><tr><td><p><tt class="literal">abs</tt></p></td><td><p>Identical to Perl's <tt class="literal">abs</tt> function</p></td></tr><tr><td><p><tt class="literal">access</tt></p></td><td><p>Determines accessibility of a file; returns <tt class="literal">undef</tt>on failure</p></td></tr><tr><td><p><tt class="literal">acos</tt></p></td><td><p>Identical to C function <tt class="literal">acos(3)</tt></p></td></tr><tr><td><p><tt class="literal">alarm</tt></p></td><td><p>Identical to Perl's <tt class="literal">alarm</tt> function</p></td></tr><tr><td><p><tt class="literal">asctime</tt></p></td><td><p>Identical to C function <tt class="literal">asctime(3)</tt></p></td></tr><tr><td><p><tt class="literal">asin</tt></p></td><td><p>Identical to C function <tt class="literal">asin(3)</tt></p></td></tr><tr><td><p><tt class="literal">assert</tt></p></td><td><p>Similar to C macro <tt class="literal">assert(3)</tt></p></td></tr><tr><td><p><tt class="literal">atan</tt></p></td><td><p>Identical to C function <tt class="literal">atan(3)</tt></p></td></tr><tr><td><p><tt class="literal">atan2</tt></p></td><td><p>Identical to Perl's <tt class="literal">atan2</tt> function</p></td></tr><tr><td><p><tt class="literal">atexit</tt></p></td><td><p>C-specific; use <tt class="literal">END {}</tt></p></td></tr><tr><td><p><tt class="literal">atof</tt></p></td><td><p>C-specific</p></td></tr><tr><td><p><tt class="literal">atoi</tt></p></td><td><p>C-specific</p></td></tr><tr><td><p><tt class="literal">atol</tt></p></td><td><p>C-specific</p></td></tr><tr><td><p><tt class="literal">bsearch</tt></p></td><td><p>Not supplied</p></td></tr><tr><td><p><tt class="literal">calloc</tt></p></td><td><p>C-specific</p></td></tr><tr><td><p><tt class="literal">ceil</tt></p></td><td><p>Identical to C function <tt class="literal">ceil(3)</tt></p></td></tr><tr><td><p><tt class="literal">chdir</tt></p></td><td><p>Identical to Perl's <tt class="literal">chdir</tt> function</p></td></tr><tr><td><p><tt class="literal">chmod</tt></p></td><td><p>Identical to Perl's <tt class="literal">chmod</tt> function</p></td></tr><tr><td><p><tt class="literal">chown</tt></p></td><td><p>Identical to Perl's <tt class="literal">chown</tt> function</p></td></tr><tr><td><p><tt class="literal">clearerr</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::clearerr</tt></p></td></tr><tr><td><p><tt class="literal">clock</tt></p></td><td><p>Identical to C function <tt class="literal">clock(3)</tt></p></td></tr><tr><td><p><tt class="literal">close</tt></p></td><td><p>Closes a file; returns <tt class="literal">undef</tt> on failure</p></td></tr><tr><td><p><tt class="literal">closedir</tt></p></td><td><p>Identical to Perl's <tt class="literal">closedir</tt>function</p></td></tr><tr><td><p><tt class="literal">cos</tt></p></td><td><p>Identical to Perl's <tt class="literal">cos</tt> function</p></td></tr><tr><td><p><tt class="literal">cosh</tt></p></td><td><p>Identical to C function <tt class="literal">cosh(3)</tt></p></td></tr><tr><td><p><tt class="literal">creat</tt></p></td><td><p>Creates a new file</p></td></tr><tr><td><p><tt class="literal">ctermid</tt></p></td><td><p>Generates pathname for the controlling terminal</p></td></tr><tr><td><p><tt class="literal">ctime</tt></p></td><td><p>Identical to C function <tt class="literal">ctime(3)</tt></p></td></tr><tr><td><p><tt class="literal">cuserid</tt></p></td><td><p>Gets user's login name</p></td></tr><tr><td><p><tt class="literal">difftime</tt></p></td><td><p>Identical to C function <tt class="literal">difftime(3)</tt></p></td></tr><tr><td><p><tt class="literal">div</tt></p></td><td><p>C-specific</p></td></tr><tr><td><p><tt class="literal">dup</tt></p></td><td><p>Similar to C function <tt class="literal">dup(2)</tt>; returns<tt class="literal">undef</tt> on failure</p></td></tr><tr><td><p><tt class="literal">dup2</tt></p></td><td><p>Similar to C function <tt class="literal">dup2(2)</tt>; returns<tt class="literal">undef</tt> on failure</p></td></tr><tr><td><p><tt class="literal">errno</tt></p></td><td><p>Returns the value of <tt class="literal">errno</tt></p></td></tr><tr><td><p><tt class="literal">execl</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">exec</tt></p></td></tr><tr><td><p><tt class="literal">execle</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">exec</tt></p></td></tr><tr><td><p><tt class="literal">execlp</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">exec</tt></p></td></tr><tr><td><p><tt class="literal">execv</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">exec</tt></p></td></tr><tr><td><p><tt class="literal">execve</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">exec</tt></p></td></tr><tr><td><p><tt class="literal">execvp</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">exec</tt></p></td></tr><tr><td><p><tt class="literal">exit</tt></p></td><td><p>Identical to Perl's <tt class="literal">exit</tt> function</p></td></tr><tr><td><p><tt class="literal">exp</tt></p></td><td><p>Identical to Perl's <tt class="literal">exp</tt> function</p></td></tr><tr><td><p><tt class="literal">fabs</tt></p></td><td><p>Identical to Perl's <tt class="literal">abs</tt> function</p></td></tr><tr><td><p><tt class="literal">fclose</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::close</tt></p></td></tr><tr><td><p><tt class="literal">fcntl</tt></p></td><td><p>Identical to Perl's <tt class="literal">fcntl</tt> function</p></td></tr><tr><td><p><tt class="literal">fdopen</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::new_from_fd</tt></p></td></tr><tr><td><p><tt class="literal">feof</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::eof</tt></p></td></tr><tr><td><p><tt class="literal">ferror</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::error</tt></p></td></tr><tr><td><p><tt class="literal">fflush</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::flush</tt></p></td></tr><tr><td><p><tt class="literal">fgetc</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::getc</tt></p></td></tr><tr><td><p><tt class="literal">fgetpos</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::getpos</tt></p></td></tr><tr><td><p><tt class="literal">fgets</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::gets</tt></p></td></tr><tr><td><p><tt class="literal">fileno</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::fileno</tt></p></td></tr><tr><td><p><tt class="literal">floor</tt></p></td><td><p>Identical to C function <tt class="literal">floor(3)</tt></p></td></tr><tr><td><p><tt class="literal">fmod</tt></p></td><td><p>Identical to C function <tt class="literal">fmod(3)</tt></p></td></tr><tr><td><p><tt class="literal">fopen</tt></p></td><td><p>Uses method <tt class="literal">FileHandle::open</tt></p></td></tr><tr><td><p><tt class="literal">fork</tt></p></td><td><p>Identical to Perl's <tt class="literal">fork</tt> function</p></td></tr><tr><td><p><tt class="literal">fpathconf</tt></p></td><td><p>Returns value of a configurable limit on a file or directory, or<tt class="literal">undef</tt> on failure</p></td></tr><tr><td><p><tt class="literal">fprintf</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">printf</tt>function</p></td></tr><tr><td><p><tt class="literal">fputc</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">print</tt>function</p></td></tr><tr><td><p><tt class="literal">fputs</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">print</tt>function</p></td></tr><tr><td><p><tt class="literal">fread</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">read</tt>function</p></td></tr><tr><td><p><tt class="literal">free</tt></p></td><td><p>C-specific</p></td></tr><tr><td><p><tt class="literal">freopen</tt></p></td><td><p>C-specific; use Perl's <tt class="literal">open</tt>function⌨️ 快捷键说明
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