242 lines
5.0 KiB
HTML
242 lines
5.0 KiB
HTML
|
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<HTML><HEAD><TITLE>Man page of ISGREATER</TITLE>
|
|
</HEAD><BODY>
|
|
<H1>ISGREATER</H1>
|
|
Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<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>
|
|
|
|
isgreater, isgreaterequal, isless, islessequal, islessgreater,
|
|
isunordered - floating-point relational tests without exception for NaN
|
|
<A NAME="lbAC"> </A>
|
|
<H2>SYNOPSIS</H2>
|
|
|
|
<PRE>
|
|
<B>#include <<A HREF="file:///usr/include/math.h">math.h</A>></B>
|
|
|
|
<B>int isgreater(</B><I>x</I><B>, </B><I>y</I><B>);</B>
|
|
|
|
<B>int isgreaterequal(</B><I>x</I><B>, </B><I>y</I><B>);</B>
|
|
|
|
<B>int isless(</B><I>x</I><B>, </B><I>y</I><B>);</B>
|
|
|
|
<B>int islessequal(</B><I>x</I><B>, </B><I>y</I><B>);</B>
|
|
|
|
<B>int islessgreater(</B><I>x</I><B>, </B><I>y</I><B>);</B>
|
|
|
|
<B>int isunordered(</B><I>x</I><B>, </B><I>y</I><B>);</B>
|
|
</PRE>
|
|
|
|
<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>
|
|
|
|
|
|
All functions described here:
|
|
<DL COMPACT><DT id="1"><DD>
|
|
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|
|
</DL>
|
|
|
|
|
|
<A NAME="lbAD"> </A>
|
|
<H2>DESCRIPTION</H2>
|
|
|
|
The normal relational operations (like
|
|
<B><</B>,
|
|
|
|
"less than")
|
|
fail if one of the operands is NaN.
|
|
This will cause an exception.
|
|
To avoid this, C99 defines the macros listed below.
|
|
<P>
|
|
|
|
These macros are guaranteed to evaluate their arguments only once.
|
|
The arguments must be of real floating-point type (note: do not pass
|
|
integer values as arguments to these macros, since the arguments will
|
|
<I>not</I>
|
|
|
|
be promoted to real-floating types).
|
|
<DL COMPACT>
|
|
<DT id="2"><B>isgreater</B>()
|
|
|
|
<DD>
|
|
determines <I>(x) > (y)</I> without an exception
|
|
if
|
|
<I>x</I>
|
|
|
|
or
|
|
<I>y</I>
|
|
|
|
is NaN.
|
|
<DT id="3"><B>isgreaterequal</B>()
|
|
|
|
<DD>
|
|
determines <I>(x) >= (y)</I> without an exception
|
|
if
|
|
<I>x</I>
|
|
|
|
or
|
|
<I>y</I>
|
|
|
|
is NaN.
|
|
<DT id="4"><B>isless</B>()
|
|
|
|
<DD>
|
|
determines <I>(x) < (y)</I> without an exception
|
|
if
|
|
<I>x</I>
|
|
|
|
or
|
|
<I>y</I>
|
|
|
|
is NaN.
|
|
<DT id="5"><B>islessequal</B>()
|
|
|
|
<DD>
|
|
determines <I>(x) <= (y)</I> without an exception
|
|
if
|
|
<I>x</I>
|
|
|
|
or
|
|
<I>y</I>
|
|
|
|
is NaN.
|
|
<DT id="6"><B>islessgreater</B>()
|
|
|
|
<DD>
|
|
determines <I>(x) < (y) || (x) > (y)</I>
|
|
without an exception if
|
|
<I>x</I>
|
|
|
|
or
|
|
<I>y</I>
|
|
|
|
is NaN.
|
|
This macro is not equivalent to <I>x != y</I> because that expression is
|
|
true if
|
|
<I>x</I>
|
|
|
|
or
|
|
<I>y</I>
|
|
|
|
is NaN.
|
|
<DT id="7"><B>isunordered</B>()
|
|
|
|
<DD>
|
|
determines whether its arguments are unordered, that is, whether
|
|
at least one of the arguments is a NaN.
|
|
</DL>
|
|
<A NAME="lbAE"> </A>
|
|
<H2>RETURN VALUE</H2>
|
|
|
|
The macros other than
|
|
<B>isunordered</B>()
|
|
|
|
return the result of the relational comparison;
|
|
these macros return 0 if either argument is a NaN.
|
|
<P>
|
|
|
|
<B>isunordered</B>()
|
|
|
|
returns 1 if
|
|
<I>x</I>
|
|
|
|
or
|
|
<I>y</I>
|
|
|
|
is NaN and 0 otherwise.
|
|
<A NAME="lbAF"> </A>
|
|
<H2>ERRORS</H2>
|
|
|
|
No errors occur.
|
|
<A NAME="lbAG"> </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>isgreater</B>(),
|
|
|
|
<B>isgreaterequal</B>(),
|
|
|
|
<B>isless</B>(),
|
|
|
|
<B>islessequal</B>(),
|
|
|
|
<B>islessgreater</B>(),
|
|
|
|
<B>isunordered</B>()
|
|
|
|
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
|
|
</TABLE>
|
|
|
|
|
|
<A NAME="lbAH"> </A>
|
|
<H2>CONFORMING TO</H2>
|
|
|
|
POSIX.1-2001, POSIX.1-2008, C99.
|
|
<A NAME="lbAI"> </A>
|
|
<H2>NOTES</H2>
|
|
|
|
Not all hardware supports these functions,
|
|
and where hardware support isn't provided, they will be emulated by macros.
|
|
This will result in a performance penalty.
|
|
Don't use these functions if NaN is of no concern for you.
|
|
<A NAME="lbAJ"> </A>
|
|
<H2>SEE ALSO</H2>
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?3+fpclassify">fpclassify</A></B>(3),
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?3+isnan">isnan</A></B>(3)
|
|
|
|
<A NAME="lbAK"> </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="8"><A HREF="#lbAB">NAME</A><DD>
|
|
<DT id="9"><A HREF="#lbAC">SYNOPSIS</A><DD>
|
|
<DT id="10"><A HREF="#lbAD">DESCRIPTION</A><DD>
|
|
<DT id="11"><A HREF="#lbAE">RETURN VALUE</A><DD>
|
|
<DT id="12"><A HREF="#lbAF">ERRORS</A><DD>
|
|
<DT id="13"><A HREF="#lbAG">ATTRIBUTES</A><DD>
|
|
<DT id="14"><A HREF="#lbAH">CONFORMING TO</A><DD>
|
|
<DT id="15"><A HREF="#lbAI">NOTES</A><DD>
|
|
<DT id="16"><A HREF="#lbAJ">SEE ALSO</A><DD>
|
|
<DT id="17"><A HREF="#lbAK">COLOPHON</A><DD>
|
|
</DL>
|
|
<HR>
|
|
This document was created by
|
|
<A HREF="/cgi-bin/man/man2html">man2html</A>,
|
|
using the manual pages.<BR>
|
|
Time: 00:05:46 GMT, March 31, 2021
|
|
</BODY>
|
|
</HTML>
|