man-pages/man3/a64l.3.html
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<H1>A64L</H1>
Section: Linux Programmer's Manual (3)<BR>Updated: 2016-03-15<BR><A HREF="#index">Index</A>
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
a64l, l64a - convert between long and base-64
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<B>#include &lt;<A HREF="file:///usr/include/stdlib.h">stdlib.h</A>&gt;</B>
<P>
<B>long a64l(const char *</B><I>str64</I><B>);</B>
<P>
<B>char *l64a(long </B><I>value</I><B>);</B>
<P>
Feature Test Macro Requirements for glibc (see
<B><A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A></B>(7)):
<P>
<B>a64l</B>(),
<B>l64a</B>():
<BR>
<DL COMPACT><DT id="1"><DD>
_XOPEN_SOURCE&nbsp;&gt;=&nbsp;500
<BR>&nbsp;&nbsp;&nbsp;&nbsp;||&nbsp;/*&nbsp;Glibc&nbsp;since&nbsp;2.19:&nbsp;*/&nbsp;_DEFAULT_SOURCE
<BR>&nbsp;&nbsp;&nbsp;&nbsp;||&nbsp;/*&nbsp;Glibc&nbsp;versions&nbsp;&lt;=&nbsp;2.19:&nbsp;*/&nbsp;_SVID_SOURCE
</DL>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
These functions provide a conversion between 32-bit long integers
and little-endian base-64 ASCII strings (of length zero to six).
If the string used as argument for
<B>a64l</B>()
has length greater than six, only the first six bytes are used.
If the type
<I>long</I>
has more than 32 bits, then
<B>l64a</B>()
uses only the low order 32 bits of
<I>value</I>,
and
<B>a64l</B>()
sign-extends its 32-bit result.
<P>
The 64 digits in the base-64 system are:
<P>
<DL COMPACT><DT id="2"><DD>
<PRE>
'.' represents a 0
'/' represents a 1
0-9 represent 2-11
A-Z represent 12-37
a-z represent 38-63
</PRE>
</DL>
<P>
So 123 = 59*64^0 + 1*64^1 = &quot;v/&quot;.
<A NAME="lbAE">&nbsp;</A>
<H2>ATTRIBUTES</H2>
For an explanation of the terms used in this section, see
<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
<TABLE BORDER>
<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
<TR VALIGN=top><TD>
<B>l64a</B>()
</TD><TD>Thread safety</TD><TD>MT-Unsafe race:l64a<BR></TD></TR>
<TR VALIGN=top><TD>
<B>a64l</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
</TABLE>
<A NAME="lbAF">&nbsp;</A>
<H2>CONFORMING TO</H2>
POSIX.1-2001, POSIX.1-2008.
<A NAME="lbAG">&nbsp;</A>
<H2>NOTES</H2>
The value returned by
<B>l64a</B>()
may be a pointer to a static buffer, possibly overwritten
by later calls.
<P>
The behavior of
<B>l64a</B>()
is undefined when
<I>value</I>
is negative.
If
<I>value</I>
is zero, it returns an empty string.
<P>
These functions are broken in glibc before 2.2.5
(puts most significant digit first).
<P>
This is not the encoding used by
<B><A HREF="/cgi-bin/man/man2html?1+uuencode">uuencode</A></B>(1).
<A NAME="lbAH">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?1+uuencode">uuencode</A></B>(1),
<B><A HREF="/cgi-bin/man/man2html?3+strtoul">strtoul</A></B>(3)
<A NAME="lbAI">&nbsp;</A>
<H2>COLOPHON</H2>
This page is part of release 5.05 of the Linux
<I>man-pages</I>
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT id="3"><A HREF="#lbAB">NAME</A><DD>
<DT id="4"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="5"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="6"><A HREF="#lbAE">ATTRIBUTES</A><DD>
<DT id="7"><A HREF="#lbAF">CONFORMING TO</A><DD>
<DT id="8"><A HREF="#lbAG">NOTES</A><DD>
<DT id="9"><A HREF="#lbAH">SEE ALSO</A><DD>
<DT id="10"><A HREF="#lbAI">COLOPHON</A><DD>
</DL>
<HR>
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Time: 00:05:35 GMT, March 31, 2021
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