ISINF(3P)                                           POSIX Programmer's Manual                                          ISINF(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

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,  Copy-
       right (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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                     ISINF(3P)