SIGNBIT(3M) Mathematical Library Functions SIGNBIT(3M)

signbit - test sign

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>
int signbit(real-floating x);

The signbit() macro determines whether the sign of its argument value is negative. NaNs, zeros, and infinities have a sign bit.

The signbit() macro returns a non-zero value if and only if the sign of its argument value is negative.

No errors are defined.

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Standard
MT-Level MT-Safe

math.h(3HEAD), fpclassify(3M), isfinite(3M), isinf(3M), isnan(3M), isnormal(3M), attributes(7), standards(7)

July 12, 2006 SunOS 5.11