ISFINITE(3) | Library Functions Manual | ISFINITE(3)

# NAME

`isfinite` —
test for finite value

# LIBRARY

Standard C Library (libc, -lc)

# SYNOPSIS

`#include <math.h>`

int
`isfinite`(real-floating x);

# DESCRIPTION

The `isfinite`() determines whether its argument x has a finite value. An argument represented in a format wider than its semantic type is converted to its semantic type first. The determination is then based on the type of the argument.

## IEEE 754

It is determined whether the value of x is zero, subnormal, or normal, and neither infinite nor NaN.

## VAX

It is determined whether the value of x is true zero or finite, and neither dirty zero nor ROP.

# RETURN VALUES

The `isfinite`() macro returns a non-zero value if the value of x is finite. Otherwise 0 is returned.

# ERRORS

No errors are defined.

# SEE ALSO

finite(3), fpclassify(3), isnormal(3), math(3), signbit(3)

# STANDARDS

The `isfinite`() macro conforms to ISO/IEC 9899:1999 (“ISO C99”).

August 6, 2011 | NetBSD 9.4