Manpage of ISGREATER

ISGREATER

Section: Linux Programmer's Manual (3)
Updated: 2016-03-15
Index
 

NAME

isgreater, isgreaterequal, isless, islessequal, islessgreater, isunordered - floating-point relational tests without exception for NaN  

SYNOPSIS

#include <math.h>int isgreater(x, y);int isgreaterequal(x, y);int isless(x, y);int islessequal(x, y);int islessgreater(x, y);int isunordered(x, y);

Link with -lm.

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

All functions described here:

_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
 

DESCRIPTION

The normal relational operations (like <, "less than") will fail if one of the operands is NaN. This will cause an exception. To avoid this, C99 defines the macros listed below.

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 notbe promoted to real-floating types).

isgreater()
determines (x) > (y) without an exception if xor yis NaN.
isgreaterequal()
determines (x) >= (y) without an exception if xor yis NaN.
isless()
determines (x) < (y) without an exception if xor yis NaN.
islessequal()
determines (x) <= (y) without an exception if xor yis NaN.
islessgreater()
determines (x) < (y) || (x) > (y)without an exception if xor yis NaN. This macro is not equivalent to x != y because that expression is true if xor yis NaN.
isunordered()
determines whether its arguments are unordered, that is, whether at least one of the arguments is a NaN.
 

RETURN VALUE

The macros other than isunordered() return the result of the relational comparison; these macros return 0 if either argument is a NaN.

isunordered() returns 1 if xor yis NaN and 0 otherwise.  

ERRORS

No errors occur.  

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).
InterfaceAttributeValue
isgreater(), isgreaterequal(), isless(), islessequal(), islessgreater(), isunordered() Thread safetyMT-Safe
 

CONFORMING TO

POSIX.1-2001, POSIX.1-2008, C99.  

NOTES

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.  

SEE ALSO

fpclassify(3), isnan(3)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
CONFORMING TO
NOTES
SEE ALSO

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Time: 22:27:52 GMT, June 20, 2016