SIGNBIT(3) Linux Programmer's Manual SIGNBIT(3)
NAME
signbit  test sign of a real floating point number
SYNOPSIS
#include <<math.h>>
int signbit(x);
Compile with std=c99; link with lm.
DESCRIPTION
signbit() is a generic macro which can work on all real floatingpoint
types. It returns a nonzero value if the value of x has its sign bit
set.
This is not the same as x < 0.0, because IEEE 754 floating point allows
zero to be signed. The comparison 0.0 < 0.0 is false, but sign
bit(0.0) will return a nonzero value.
CONFORMING TO
C99. This function is defined in IEC 559 (and the appendix with recom
mended functions in IEEE 754/IEEE 854).
SEE ALSO
copysign(3)
COLOPHON
This page is part of release 3.05 of the Linux manpages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/manpages/.
GNU 20020810 SIGNBIT(3)
