Tests the sign.
#include <math.h>
int signbit (x)
real-floating x;The signbit macro determines whether the sign of its argument value is negative. NaNs, zeros, and infinities have a sign bit.
| Item | Description |
|---|---|
| x | Specifies the value to be tested. |
The signbit macro returns a nonzero value if the sign of its argument value is negative.