NAME

       signbit - test sign

SYNOPSIS

       #include <math.h>

       int signbit(real-floating x);

DESCRIPTION

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

RETURN VALUE

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

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       fpclassify()  ,  isfinite() , isinf() , isnan() , isnormal() , the Base Definitions volume
       of IEEE Std 1003.1-2001, <math.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1,  2003  Edition,  Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  by
       the  Institute  of  Electrical  and  Electronics Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .