isinf
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Defined in header
<math.h>
#define isinf(arg) /* implementation defined */
(since C99)
Determines if the given floating-point number arg is positive or negative infinity. The macro returns an integral value.
FLT_EVAL_METHOD is ignored: even if the argument is evaluated with more range and precision than its type, it is first converted to its semantic type, and the classification is based on that.
[edit] Parameters
arg
-
floating-point value
[edit] Return value
Nonzero integral value if arg has an infinite value, 0 otherwise.
[edit] Example
Run this code
#include <stdio.h> #include <math.h> #include <float.h> int main(void) { printf ("isinf(NAN) = %d\n", isinf(NAN)); printf ("isinf(INFINITY) = %d\n", isinf(INFINITY)); printf ("isinf(0.0) = %d\n", isinf(0.0)); printf ("isinf(DBL_MIN/2.0) = %d\n", isinf(DBL_MIN /2.0)); printf ("isinf(1.0) = %d\n", isinf(1.0)); printf ("isinf(exp(800)) = %d\n", isinf(exp (800))); }
Possible output:
isinf(NAN) = 0 isinf(INFINITY) = 1 isinf(0.0) = 0 isinf(DBL_MIN/2.0) = 0 isinf(1.0) = 0 isinf(exp(800)) = 1
[edit] References
- C17 standard (ISO/IEC 9899:2018):
- 7.12.3.3 The isinf macro (p: 172)
- C11 standard (ISO/IEC 9899:2011):
- 7.12.3.3 The isinf macro (p: 236)
- C99 standard (ISO/IEC 9899:1999):
- 7.12.3.3 The isinf macro (p: 217)
[edit] See also
C++ documentation for isinf