isunordered
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Defined in header
<math.h>
#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
Run this code
#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)
[edit] See also
C++ documentation for isunordered