Name
isgreater, isgreaterequal, isless, islessequal, islessgreater, isunordered — macros to test a relation
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); |
![[Note]](../stylesheet/note.png) |
Note |
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Compile with |
DESCRIPTION
The normal relation operations (like less) will fail if one of the operands is NaN. This will cause an exception. To avoid this, C99 defines these macros. The macros are guaranteed to evaluate their operands only once. The operand can be of any real floating-point type.
isgreater()-
determines (x) > (y) without an exception if
xoryis NaN. isgreaterequal()-
determines (x) >= (y) without an exception if
xoryis NaN. isless()-
determines (x) < (y) without an exception if
xoryis NaN. islessequal()-
determines (x) <= (y) without an exception if
xoryis NaN. islessgreater()-
determines (x) < (y) || (x) > (y) without an exception if
xoryis NaN. This macro is not equivalent to x != y because that expression is true ifxoryis NaN. isunordered()-
is true if
xoryis NaN and false otherwise.
NOTES
Not all hardware supports these functions, and where it doesn't, they will be emulated by macros. This will give you a performance penalty. Don't use these functions if NaN is of no concern for you.