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<HTML><HEAD><TITLE>Manpage of IPSEC_ATOUL</TITLE>
</HEAD><BODY>
<H1>IPSEC_ATOUL</H1>
Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>


<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>

ipsec atoul, ultoa - convert unsigned-long numbers to and from ASCII
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>

<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>

<P>
<B>const char *atoul(const char *src, size_t srclen,</B>

<BR>
&nbsp;
<B>int base, unsigned long *n);</B>

<BR>

<B>size_t ultoa(unsigned long n, int base, char *dst,</B>

<BR>
&nbsp;
<B>size_t dstlen);</B>

<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>

These functions are obsolete; see
<I><A HREF="ipsec_ttoul.3.html">ipsec_ttoul</A></I>(3)

for their replacements.
<P>

<I>Atoul</I>

converts an ASCII number into a binary
<B>unsigned long</B>

value.
<I>Ultoa</I>

does the reverse conversion, back to an ASCII version.
<P>

Numbers are specified in ASCII as
decimal (e.g.
<B>123</B>),

octal with a leading zero (e.g.
<B>012</B>,

which has value 10),
or hexadecimal with a leading
<B>0x</B>

(e.g.
<B>0x1f</B>,

which has value 31)
in either upper or lower case.
<P>

The
<I>srclen</I>

parameter of
<I>atoul</I>

specifies the length of the ASCII string pointed to by
<I>src</I>;

it is an error for there to be anything else
(e.g., a terminating NUL) within that length.
As a convenience for cases where an entire NUL-terminated string is
to be converted,
a
<I>srclen</I>

value of
<B>0</B>

is taken to mean
<B>strlen(src)</B>.

<P>

The
<I>base</I>

parameter of
<I>atoul</I>

can be
<B>8</B>,

<B>10</B>,

or
<B>16</B>,

in which case the number supplied is assumed to be of that form
(and in the case of
<B>16</B>,

to lack any
<B>0x</B>

prefix).
It can also be
<B>0</B>,

in which case the number is examined for a leading zero
or a leading
<B>0x</B>

to determine its base,
or
<B>13</B>

(halfway between 10 and 16),
which has the same effect as
<B>0</B>

except that a non-hexadecimal
number is considered decimal regardless of any leading zero.
<P>

The
<I>dstlen</I>

parameter of
<I>ultoa</I>

specifies the size of the
<I>dst</I>

parameter;
under no circumstances are more than
<I>dstlen</I>

bytes written to
<I>dst</I>.

A result which will not fit is truncated.
<I>Dstlen</I>

can be zero, in which case
<I>dst</I>

need not be valid and no result is written,
but the return value is unaffected;
in all other cases, the (possibly truncated) result is NUL-terminated.
<P>

The
<I>base</I>

parameter of
<I>ultoa</I>

must be
<B>8</B>,

<B>10</B>,

or
<B>16</B>.

<P>

<I>Atoul</I>

returns NULL for success and
a pointer to a string-literal error message for failure;
see DIAGNOSTICS.
<I>Ultoa</I>

returns the size of buffer which would 
be needed to
accommodate the full conversion result, including terminating NUL;
it is the caller's responsibility to check this against the size of
the provided buffer to determine whether truncation has occurred.
<A NAME="lbAE">&nbsp;</A>
<H2>SEE ALSO</H2>

<A HREF="atol.3.html">atol</A>(3), <A HREF="strtoul.3.html">strtoul</A>(3)
<A NAME="lbAF">&nbsp;</A>
<H2>DIAGNOSTICS</H2>

Fatal errors in
<I>atoul</I>

are:
empty input;
unknown
<I>base</I>;

non-digit character found;
number too large for an
<B>unsigned long</B>.

<A NAME="lbAG">&nbsp;</A>
<H2>HISTORY</H2>

Written for the FreeS/WAN project by Henry Spencer.
<A NAME="lbAH">&nbsp;</A>
<H2>BUGS</H2>

There is no provision for reporting an invalid
<I>base</I>

parameter given to
<I>ultoa</I>.

<P>

The restriction of error reports to literal strings
(so that callers don't need to worry about freeing them or copying them)
does limit the precision of error reporting.
<P>

The error-reporting convention lends itself to slightly obscure code,
because many readers will not think of NULL as signifying success.
A good way to make it clearer is to write something like:
<P>

<DL COMPACT><DT><DD>
<PRE>
<B>const char *error;</B>

<B>error = atoul( /* ... */ );</B>
<B>if (error != NULL) {</B>
<B>        /* something went wrong */</B>
</PRE>

</DL>

<P>

<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT><A HREF="#lbAB">NAME</A><DD>
<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT><A HREF="#lbAE">SEE ALSO</A><DD>
<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
<DT><A HREF="#lbAG">HISTORY</A><DD>
<DT><A HREF="#lbAH">BUGS</A><DD>
</DL>
<HR>
This document was created by
<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
using the manual pages.<BR>
Time: 21:40:18 GMT, November 11, 2003
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