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/* isgreater.c: This file contains no source code, but rather only the
* man-page comments. All of the documented "functions" are actually macros
* defined in math.h (q.v.). */
/*
FUNCTION
<<isgreater>>, <<isgreaterequal>>, <<isless>>, <<islessequal>>, <<islessgreater>>, and <<isunordered>>--comparison macros
INDEX
isgreater
INDEX
isgreaterequal
INDEX
isless
INDEX
islessequal
INDEX
islessgreater
INDEX
isunordered
ANSI_SYNOPSIS
#include <math.h>
int isgreater(real-floating <[x]>, real-floating <[y]>);
int isgreaterequal(real-floating <[x]>, real-floating <[y]>);
int isless(real-floating <[x]>, real-floating <[y]>);
int islessequal(real-floating <[x]>, real-floating <[y]>);
int islessgreater(real-floating <[x]>, real-floating <[y]>);
int isunordered(real-floating <[x]>, real-floating <[y]>);
DESCRIPTION
<<isgreater>>, <<isgreaterequal>>, <<isless>>, <<islessequal>>,
<<islessgreater>>, and <<isunordered>> are macros defined for use in
comparing floating-point numbers without raising any floating-point
exceptions.
The relational operators (i.e. <, >, <=, and >=) support the usual mathematical
relationships between numeric values. For any ordered pair of numeric
values exactly one of the relationships--less, greater, and equal--is
true. Relational operators may raise the "invalid" floating-point
exception when argument values are NaNs. For a NaN and a numeric value, or
for two NaNs, just the unordered relationship is true (i.e., if one or both
of the arguments a NaN, the relationship is called unordered). The specified
macros are quiet (non floating-point exception raising) versions of the
relational operators, and other comparison macros that facilitate writing
efficient code that accounts for NaNs without suffering the "invalid"
floating-point exception. In the synopses shown, "real-floating" indicates
that the argument is an expression of real floating type.
Please note that saying that the macros do not raise floating-point
exceptions, it is referring to the function that they are performing. It
is certainly possible to give them an expression which causes an exception.
For example:
o+
o NaN < 1.0
causes an "invalid" exception,
o isless(NaN, 1.0)
does not, and
o isless(NaN*0., 1.0)
causes an exception due to the "NaN*0.", but not from the
resultant reduced comparison of isless(NaN, 1.0).
o-
RETURNS
@comment Formatting note: "$@" forces a new line
No floating-point exceptions are raised for any of the macros.@*
The <<isgreater>> macro returns the value of (x) > (y).@*
The <<isgreaterequal>> macro returns the value of (x) >= (y).@*
The <<isless>> macro returns the value of (x) < (y).@*
The <<islessequal>> macro returns the value of (x) <= (y).@*
The <<islessgreater>> macro returns the value of (x) < (y) || (x) > (y).@*
The <<isunordered>> macro returns 1 if either of its arguments is NaN and 0 otherwise.
PORTABILITY
C99, POSIX.
*/
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