NAME

isinf - test for infinity

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS



int isinf(real-floating x)

DESCRIPTION

The isinf() macro determines whether its argument x is an infinity (positive or negative). 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 an infinity.

VAX

Infinities are not supported.

RETURN VALUES

The isinf() macro returns a non-zero value if the value of x is an infinity. Otherwise 0 is returned.

SEE ALSO

fpclassify(3), isfinite(3), isinff(3), isnan(3), isnanf(3), isnormal(3), math(3), signbit(3)

STANDARDS

The isinf() macro conforms to ISO/IEC 9899:1999 (``ISO C99'') .