SIGNBIT(3)		   Linux Programmers Manual		   SIGNBIT(3)



NAME
       signbit - test sign of a real floating point number

SYNOPSIS
       #include 

       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  sign
       bit(-0.0) will return a non-zero 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  man-pages  project.   A
       description  of	the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



GNU				  2002-08-10			    SIGNBIT(3)