191 lines
4.7 KiB
HTML
191 lines
4.7 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of MKTEMP</TITLE>
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</HEAD><BODY>
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<H1>MKTEMP</H1>
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Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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mktemp - make a unique temporary filename
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<PRE>
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<B>#include <<A HREF="file:///usr/include/stdlib.h">stdlib.h</A>></B>
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<B>char *mktemp(char *</B><I>template</I><B>);</B>
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</PRE>
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<P>
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Feature Test Macro Requirements for glibc (see
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<B><A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A></B>(7)):
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<P>
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<B>mktemp</B>():
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<DL COMPACT><DT id="1"><DD>
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<DL COMPACT>
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<DT id="2">Since glibc 2.12:<DD>
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(_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200112L)
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<BR> || /* Glibc since 2.19: */ _DEFAULT_SOURCE
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<BR> || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
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<DT id="3">Before glibc 2.12:<DD>
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_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500
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</DL>
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</DL>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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<I>Never use this function</I>;
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see BUGS.
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<P>
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The
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<B>mktemp</B>()
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function generates a unique temporary filename
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from <I>template</I>.
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The last six characters of <I>template</I> must
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be XXXXXX and these are replaced with a string that makes the
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filename unique.
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Since it will be modified,
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<I>template</I>
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must not be a string constant, but should be declared as a character array.
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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The
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<B>mktemp</B>()
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function always returns <I>template</I>.
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If a unique name was created, the last six bytes of <I>template</I> will
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have been modified in such a way that the resulting name is unique
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(i.e., does not exist already)
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If a unique name could not be created,
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<I>template</I> is made an empty string, and
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<I>errno</I>
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is set to indicate the error.
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<A NAME="lbAF"> </A>
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<H2>ERRORS</H2>
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<DL COMPACT>
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<DT id="4"><B>EINVAL</B>
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<DD>
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The last six characters of <I>template</I> were not XXXXXX.
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</DL>
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<A NAME="lbAG"> </A>
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<H2>ATTRIBUTES</H2>
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For an explanation of the terms used in this section, see
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<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
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<TABLE BORDER>
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<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
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<TR VALIGN=top><TD>
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<B>mktemp</B>()
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</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
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</TABLE>
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<A NAME="lbAH"> </A>
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<H2>CONFORMING TO</H2>
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4.3BSD, POSIX.1-2001.
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POSIX.1-2008 removes the specification of
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<B>mktemp</B>().
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<A NAME="lbAI"> </A>
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<H2>BUGS</H2>
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Never use
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<B>mktemp</B>().
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Some implementations follow 4.3BSD
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and replace XXXXXX by the current process ID and a single letter,
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so that at most 26 different names can be returned.
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Since on the one hand the names are easy to guess, and on the other
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hand there is a race between testing whether the name exists and
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opening the file, every use of
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<B>mktemp</B>()
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is a security risk.
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The race is avoided by
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<B><A HREF="/cgi-bin/man/man2html?3+mkstemp">mkstemp</A></B>(3)
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and
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<B><A HREF="/cgi-bin/man/man2html?3+mkdtemp">mkdtemp</A></B>(3).
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<A NAME="lbAJ"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?1+mktemp">mktemp</A></B>(1),
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<B><A HREF="/cgi-bin/man/man2html?3+mkdtemp">mkdtemp</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+mkstemp">mkstemp</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+tempnam">tempnam</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+tmpfile">tmpfile</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+tmpnam">tmpnam</A></B>(3)
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<A NAME="lbAK"> </A>
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<H2>COLOPHON</H2>
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This page is part of release 5.05 of the Linux
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<I>man-pages</I>
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project.
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A description of the project,
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information about reporting bugs,
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and the latest version of this page,
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can be found at
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<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="5"><A HREF="#lbAB">NAME</A><DD>
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<DT id="6"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="7"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="8"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="9"><A HREF="#lbAF">ERRORS</A><DD>
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<DT id="10"><A HREF="#lbAG">ATTRIBUTES</A><DD>
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<DT id="11"><A HREF="#lbAH">CONFORMING TO</A><DD>
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<DT id="12"><A HREF="#lbAI">BUGS</A><DD>
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<DT id="13"><A HREF="#lbAJ">SEE ALSO</A><DD>
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<DT id="14"><A HREF="#lbAK">COLOPHON</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:05:48 GMT, March 31, 2021
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</BODY>
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</HTML>
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