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NAME

       isinf - test for infinity

SYNOPSIS

       #include <math.h>

       int isinf(real-floating x);

DESCRIPTION

       The  isinf()  macro  shall  determine  whether its argument value is an
       infinity (positive or negative). First, an argument  represented  in  a
       format  wider than its semantic type is converted to its semantic type.
       Then determination is based on the type of the argument.

RETURN VALUE

       The isinf() macro shall return a non-zero value  if  and  only  if  its
       argument has an infinite value.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       fpclassify() , isfinite() , isnan() , isnormal() , signbit() , 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 .