31 lines
5 KiB
HTML
31 lines
5 KiB
HTML
<!-- Common Lisp HyperSpec (TM), version 7.0 generated by Kent M. Pitman on Mon, 11-Apr-2005 2:31am EDT -->
|
|
<HTML>
|
|
<HEAD>
|
|
<TITLE>CLHS: Section 20.1.3.1</TITLE>
|
|
<LINK HREF="../Data/clhs.css" REL="stylesheet" TYPE="text/css" />
|
|
<META HTTP-EQUIV="Author" CONTENT="Kent M. Pitman">
|
|
<META HTTP-EQUIV="Organization" CONTENT="LispWorks Ltd.">
|
|
<LINK REL=TOP HREF="../Front/index.htm">
|
|
<LINK REL=COPYRIGHT HREF="../Front/Help.htm#Legal">
|
|
<LINK REL=DISCLAIMER HREF="../Front/Help.htm#Disclaimer">
|
|
<LINK REL=PREV HREF="20_ac.htm">
|
|
<LINK REL=UP HREF="20_ac.htm">
|
|
<LINK REL=NEXT HREF="c_files.htm">
|
|
</HEAD>
|
|
<BODY>
|
|
<H1><A REV=MADE HREF="http://www.lispworks.com/"><IMG WIDTH=80 HEIGHT=65 ALT="[LISPWORKS]" SRC="../Graphics/LWSmall.gif" ALIGN=Bottom></A><A REL=TOP HREF="../Front/index.htm"><IMG WIDTH=237 HEIGHT=65 ALT="[Common Lisp HyperSpec (TM)]" SRC="../Graphics/CLHS_Sm.gif" ALIGN=Bottom></A> <A REL=PREV HREF="20_ac.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="20_ac.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="c_files.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
|
|
|
|
<HR>
|
|
|
|
<H2>
|
|
20.1.3.1 Examples of Truenames</H2> <P>
|
|
For example, a DEC TOPS-20 system with <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>files</I></A> <TT>PS:<JOE>FOO.TXT.1</TT> and <TT>PS:<JOE>FOO.TXT.2</TT> might permit the second <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>file</I></A> to be referred to as <TT>PS:<JOE>FOO.TXT.0</TT>, since the ``<TT>.0</TT>'' notation denotes ``newest'' version of several <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>files</I></A>. In the same <A REL=DEFINITION HREF="26_glo_f.htm#file_system"><I>file system</I></A>, a ``logical device'' ``<TT>JOE:</TT>'' might be taken to refer to <TT>PS:<JOE></TT>'' and so the names <TT>JOE:FOO.TXT.2</TT> or <TT>JOE:FOO.TXT.0</TT> might refer to <TT>PS:<JOE>FOO.TXT.2</TT>. In all of these cases, the <A REL=DEFINITION HREF="26_glo_t.htm#truename"><I>truename</I></A> of the file would probably be <TT>PS:<JOE>FOO.TXT.2</TT>. <P>
|
|
If a <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>file</I></A> is a symbolic link to another <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>file</I></A> (in a <A REL=DEFINITION HREF="26_glo_f.htm#file_system"><I>file system</I></A> permitting such a thing), it is conventional for the <A REL=DEFINITION HREF="26_glo_t.htm#truename"><I>truename</I></A> to be the canonical name of the <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>file</I></A> after any symbolic links have been followed; that is, it is the canonical name of the <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>file</I></A> whose contents would become available if an <A REL=DEFINITION HREF="26_glo_i.htm#input"><I>input</I></A> <A REL=DEFINITION HREF="26_glo_s.htm#stream"><I>stream</I></A> to that <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>file</I></A> were opened. <P>
|
|
In the case of a <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>file</I></A> still being created (that is, of an <A REL=DEFINITION HREF="26_glo_o.htm#output"><I>output</I></A> <A REL=DEFINITION HREF="26_glo_s.htm#stream"><I>stream</I></A> open to such a <A REL=DEFINITION HREF="26_glo_f.htm#file"><I>file</I></A>), the exact <A REL=DEFINITION HREF="26_glo_t.htm#truename"><I>truename</I></A> of the file might not be known until the <A REL=DEFINITION HREF="26_glo_s.htm#stream"><I>stream</I></A> is closed. In this case, the <A REL=DEFINITION HREF="26_glo_f.htm#function"><I>function</I></A> <A REL=DEFINITION HREF="f_tn.htm#truename"><B>truename</B></A> might return different values for such a <A REL=DEFINITION HREF="26_glo_s.htm#stream"><I>stream</I></A> before and after it was closed. In fact, before it is closed, the name returned might not even be a valid name in the <A REL=DEFINITION HREF="26_glo_f.htm#file_system"><I>file system</I></A>---for example, while a file is being written, it might have version <TT>:newest</TT> and might only take on a specific numeric value later when the file is closed even in a <A REL=DEFINITION HREF="26_glo_f.htm#file_system"><I>file system</I></A> where all files have numeric versions. <P>
|
|
<HR>
|
|
|
|
<A REL=NAVIGATOR HREF="../Front/StartPts.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Starting Points]" SRC="../Graphics/StartPts.gif" ALIGN=Bottom></A><A REL=TOC HREF="../Front/Contents.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Contents]" SRC="../Graphics/Contents.gif" ALIGN=Bottom></A><A REL=INDEX HREF="../Front/X_Master.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Index]" SRC="../Graphics/Index.gif" ALIGN=Bottom></A><A REL=INDEX HREF="../Front/X_Symbol.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Symbols]" SRC="../Graphics/Symbols.gif" ALIGN=Bottom></A><A REL=GLOSSARY HREF="../Body/26_a.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Glossary]" SRC="../Graphics/Glossary.gif" ALIGN=Bottom></A><A HREF="../Front/X3J13Iss.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Issues]" SRC="../Graphics/Issues.gif" ALIGN=Bottom></A><BR>
|
|
|
|
<A REL=COPYRIGHT HREF="../Front/Help.htm#Legal"><I>Copyright 1996-2005, LispWorks Ltd. All rights reserved.</I></A><P>
|
|
</BODY>
|
|
</HTML>
|