132 lines
3.4 KiB
HTML
132 lines
3.4 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 ASPRINTF</TITLE>
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</HEAD><BODY>
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<H1>ASPRINTF</H1>
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Section: Linux Programmer's Manual (3)<BR>Updated: 2019-03-06<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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asprintf, vasprintf - print to allocated string
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<B>#define _GNU_SOURCE</B> /* See <A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A>(7) */
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<BR>
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<B>#include <<A HREF="file:///usr/include/stdio.h">stdio.h</A>></B>
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<P>
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<B>int asprintf(char **</B><I>strp</I><B>, const char *</B><I>fmt</I><B>, ...);</B>
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<P>
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<B>int vasprintf(char **</B><I>strp</I><B>, const char *</B><I>fmt</I><B>, va_list </B><I>ap</I><B>);</B>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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The functions
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<B>asprintf</B>()
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and
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<B>vasprintf</B>()
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are analogs of
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<B><A HREF="/cgi-bin/man/man2html?3+sprintf">sprintf</A></B>(3)
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and
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<B><A HREF="/cgi-bin/man/man2html?3+vsprintf">vsprintf</A></B>(3),
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except that they allocate a string large enough to hold the output
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including the terminating null byte ('\0'),
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and return a pointer to it via the first argument.
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This pointer should be passed to
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<B><A HREF="/cgi-bin/man/man2html?3+free">free</A></B>(3)
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to release the allocated storage when it is no longer needed.
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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When successful, these functions return the number of bytes printed,
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just like
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<B><A HREF="/cgi-bin/man/man2html?3+sprintf">sprintf</A></B>(3).
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If memory allocation wasn't possible, or some other error occurs,
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these functions will return -1, and the contents of
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<I>strp</I>
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are undefined.
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<A NAME="lbAF"> </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>asprintf</B>(),
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<B>vasprintf</B>()
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</TD><TD>Thread safety</TD><TD>MT-Safe locale<BR></TD></TR>
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</TABLE>
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<P>
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<A NAME="lbAG"> </A>
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<H2>CONFORMING TO</H2>
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These functions are GNU extensions, not in C or POSIX.
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They are also available under *BSD.
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The FreeBSD implementation sets
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<I>strp</I>
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to NULL on error.
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<A NAME="lbAH"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?3+free">free</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+malloc">malloc</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+printf">printf</A></B>(3)
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<A NAME="lbAI"> </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="1"><A HREF="#lbAB">NAME</A><DD>
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<DT id="2"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="3"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="4"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="5"><A HREF="#lbAF">ATTRIBUTES</A><DD>
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<DT id="6"><A HREF="#lbAG">CONFORMING TO</A><DD>
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<DT id="7"><A HREF="#lbAH">SEE ALSO</A><DD>
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<DT id="8"><A HREF="#lbAI">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: 00:05:35 GMT, March 31, 2021
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</BODY>
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</HTML>
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