mirror of
https://github.com/autc04/Retro68.git
synced 2024-11-28 05:51:04 +00:00
76 lines
2.9 KiB
C
76 lines
2.9 KiB
C
/* 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.
|
|
|
|
*/
|