SIGNBIT(3) Library Functions Manual SIGNBIT(3)

NAME

signbittest sign

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <math.h>

int
signbit(real-floating x);

DESCRIPTION

The signbit() macro determines whether the sign of its argument value x is 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.

IEEE754

The sign is determined for all values, including infinities, zeroes, and NaNs

VAX

The sign is determined for finites, true zeros, and dirty zeroes; for ROPs the sign is reported negative.

RETURN VALUES

The signbit() macro returns a non-zero value if the sign of its value x is negative. Otherwise 0 is returned.

ERRORS

No errors are defined.

SEE ALSO

fpclassify(3), isfinite(3), isnormal(3), math(3)

STANDARDS

The signbit() macro conforms to ISO/IEC 9899:1999 (“ISO C99”).
October 29, 2003 NetBSD 6.1