171 lines
3.5 KiB
HTML
171 lines
3.5 KiB
HTML
|
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<HTML><HEAD><TITLE>Man page of NAN</TITLE>
|
|
</HEAD><BODY>
|
|
<H1>NAN</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"> </A>
|
|
<H2>NAME</H2>
|
|
|
|
nan, nanf, nanl - return 'Not a Number'
|
|
<A NAME="lbAC"> </A>
|
|
<H2>SYNOPSIS</H2>
|
|
|
|
<B>#include <<A HREF="file:///usr/include/math.h">math.h</A>></B>
|
|
|
|
<P>
|
|
|
|
<B>double nan(const char *</B><I>tagp</I><B>);</B>
|
|
|
|
<BR>
|
|
|
|
<B>float nanf(const char *</B><I>tagp</I><B>);</B>
|
|
|
|
<BR>
|
|
|
|
<B>long double nanl(const char *</B><I>tagp</I><B>);</B>
|
|
|
|
<P>
|
|
|
|
Link with <I>-lm</I>.
|
|
<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>nan</B>(),
|
|
|
|
<B>nanf</B>(),
|
|
|
|
<B>nanl</B>():
|
|
|
|
<DL COMPACT><DT id="1"><DD>
|
|
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|
|
</DL>
|
|
|
|
|
|
<A NAME="lbAD"> </A>
|
|
<H2>DESCRIPTION</H2>
|
|
|
|
These functions return a representation (determined by
|
|
<I>tagp</I>)
|
|
|
|
of a quiet NaN.
|
|
If the implementation does not support
|
|
quiet NaNs, these functions return zero.
|
|
<P>
|
|
|
|
The call
|
|
<I>nan(char-sequence)</I>
|
|
|
|
is equivalent to:
|
|
<P>
|
|
|
|
|
|
|
|
strtod("NAN(char-sequence)", NULL);
|
|
|
|
|
|
<P>
|
|
|
|
Similarly, calls to
|
|
<B>nanf</B>()
|
|
|
|
and
|
|
<B>nanl</B>()
|
|
|
|
are equivalent to analogous calls to
|
|
<B><A HREF="/cgi-bin/man/man2html?3+strtof">strtof</A></B>(3)
|
|
|
|
and
|
|
<B><A HREF="/cgi-bin/man/man2html?3+strtold">strtold</A></B>(3).
|
|
|
|
<P>
|
|
|
|
The argument
|
|
<I>tagp</I>
|
|
|
|
is used in an unspecified manner.
|
|
On IEEE 754 systems, there are many representations of NaN, and
|
|
<I>tagp</I>
|
|
|
|
selects one.
|
|
On other systems it may do nothing.
|
|
<A NAME="lbAE"> </A>
|
|
<H2>VERSIONS</H2>
|
|
|
|
These functions first appeared in glibc in version 2.1.
|
|
<A NAME="lbAF"> </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>nan</B>(),
|
|
|
|
<B>nanf</B>(),
|
|
|
|
<B>nanl</B>()
|
|
|
|
</TD><TD>Thread safety</TD><TD>MT-Safe locale<BR></TD></TR>
|
|
</TABLE>
|
|
|
|
<A NAME="lbAG"> </A>
|
|
<H2>CONFORMING TO</H2>
|
|
|
|
C99, POSIX.1-2001, POSIX.1-2008.
|
|
See also IEC 559 and the appendix with
|
|
recommended functions in IEEE 754/IEEE 854.
|
|
<A NAME="lbAH"> </A>
|
|
<H2>SEE ALSO</H2>
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?3+isnan">isnan</A></B>(3),
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?3+strtod">strtod</A></B>(3),
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?7+math_error">math_error</A></B>(7)
|
|
|
|
<A NAME="lbAI"> </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"> </A><H2>Index</H2>
|
|
<DL>
|
|
<DT id="2"><A HREF="#lbAB">NAME</A><DD>
|
|
<DT id="3"><A HREF="#lbAC">SYNOPSIS</A><DD>
|
|
<DT id="4"><A HREF="#lbAD">DESCRIPTION</A><DD>
|
|
<DT id="5"><A HREF="#lbAE">VERSIONS</A><DD>
|
|
<DT id="6"><A HREF="#lbAF">ATTRIBUTES</A><DD>
|
|
<DT id="7"><A HREF="#lbAG">CONFORMING TO</A><DD>
|
|
<DT id="8"><A HREF="#lbAH">SEE ALSO</A><DD>
|
|
<DT id="9"><A HREF="#lbAI">COLOPHON</A><DD>
|
|
</DL>
|
|
<HR>
|
|
This document was created by
|
|
<A HREF="/cgi-bin/man/man2html">man2html</A>,
|
|
using the manual pages.<BR>
|
|
Time: 00:05:48 GMT, March 31, 2021
|
|
</BODY>
|
|
</HTML>
|