SIGNBIT

Section: libc math functions (3)
Updated: 2002-08-10
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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 floating-point types. It returns a non-zero 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 `signbit (-0.0)' will return a non-zero value.  

CONFORMING TO

C99. This function is defined in IEC 559 (and the appendix with recommended functions in IEEE 754/IEEE 854).  

SEE ALSO

copysign(3)


 

Index

NAME
SYNOPSIS
DESCRIPTION
CONFORMING TO
SEE ALSO

linux.jgfs.net manual pages