Anteckning
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Determines whether a floating-point value is an infinity.
Syntax
int isinf(
/* floating-point */ x
); /* C-only macro */
template <class FloatingType>
inline bool isinf(
FloatingType x
) throw(); /* C++-only template function */
Parameters
x
The floating-point value to test.
Return value
isinf returns a nonzero value (true in C++ code) if the argument x is a positive or negative infinity. isinf returns 0 (false in C++ code) if the argument is finite or a NAN. Both normal and subnormal floating-point values are considered finite.
Remarks
isinf is a macro when compiled as C, and an inline template function when compiled as C++.
Requirements
| Function | Required header (C) | Required header (C++) |
|---|---|---|
isinf |
<math.h> | <math.h> or <cmath> |
For more compatibility information, see Compatibility.
See also
Math and floating-point support
fpclassify
_fpclass, _fpclassf
isfinite, _finite, _finitef
isnan, _isnan, _isnanf
isnormal