isfinite - cppreference.com (original) (raw)
| | | | | ---------------------------------------------------- | | ----------- | | #define isfinite(arg) /* implementation defined */ | | (since C99) |
Determines if the given floating-point number arg has finite value i.e. it is normal, subnormal or zero, but not infinite or NaN. 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 finite value, 0 otherwise.
[edit] Example
#include <float.h> #include <math.h> #include <stdio.h> int main(void) { printf("isfinite(NAN) = %d\n", isfinite(NAN)); printf("isfinite(INFINITY) = %d\n", isfinite(INFINITY)); printf("isfinite(0.0) = %d\n", isfinite(0.0)); printf("isfinite(DBL_MIN/2.0) = %d\n", isfinite(DBL_MIN / 2.0)); printf("isfinite(1.0) = %d\n", isfinite(1.0)); printf("isfinite(exp(800)) = %d\n", isfinite(exp(800))); }
Possible output:
isfinite(NAN) = 0 isfinite(INFINITY) = 0 isfinite(0.0) = 1 isfinite(DBL_MIN/2.0) = 1 isfinite(1.0) = 1 isfinite(exp(800)) = 0
[edit] References
C23 standard (ISO/IEC 9899:2024):
7.12.3.2 The isfinite macro (p: TBD)
C17 standard (ISO/IEC 9899:2018):
7.12.3.2 The isfinite macro (p: TBD)
C11 standard (ISO/IEC 9899:2011):
7.12.3.2 The isfinite macro (p: 236)
C99 standard (ISO/IEC 9899:1999):
7.12.3.2 The isfinite macro (p: 216-217)