isunordered - cppreference.com (original) (raw)
| | | | | -------------------------------------------------------- | | ----------- | | #define isunordered(x, y) /* implementation defined */ | | (since C99) |
Determines if the floating point numbers x and y are unordered, that is, one or both are NaN and thus cannot be meaningfully compared with each other.
[edit] Parameters
| x | - | floating point value |
|---|---|---|
| y | - | floating point value |
[edit] Return value
Nonzero integral value if either x or y is NaN, 0 otherwise.
[edit] Example
#include <math.h> #include <stdio.h> int main(void) { printf("isunordered(NAN,1.0) = %d\n", isunordered(NAN, 1.0)); printf("isunordered(1.0,NAN) = %d\n", isunordered(1.0, NAN)); printf("isunordered(NAN,NAN) = %d\n", isunordered(NAN, NAN)); printf("isunordered(1.0,0.0) = %d\n", isunordered(1.0, 0.0)); return 0; }
Possible output:
isunordered(NAN,1.0) = 1 isunordered(1.0,NAN) = 1 isunordered(NAN,NAN) = 1 isunordered(1.0,0.0) = 0
[edit] References
C23 standard (ISO/IEC 9899:2024):
7.12.14.6 The isunordered macro (p: TBD)
F.10.11 Comparison macros (p: TBD)
C17 standard (ISO/IEC 9899:2018):
7.12.14.6 The isunordered macro (p: TBD)
F.10.11 Comparison macros (p: TBD)
C11 standard (ISO/IEC 9899:2011):
7.12.14.6 The isunordered macro (p: 261)
F.10.11 Comparison macros (p: 531)
C99 standard (ISO/IEC 9899:1999):
7.12.14.6 The isunordered macro (p: 242)