isnan(3p) — Linux manual page

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

PROLOG         top

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

NAME         top

       isnan — test for a NaN

SYNOPSIS         top

       #include <math.h>

       int isnan(real-floating x);

DESCRIPTION         top

       The functionality described on this reference page is aligned
       with the ISO C standard. Any conflict between the requirements
       described here and the ISO C standard is unintentional. This
       volume of POSIX.1‐2017 defers to the ISO C standard.

       The isnan() macro shall determine whether its argument value is a
       NaN. 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         top

       The isnan() macro shall return a non-zero value if and only if
       its argument has a NaN value.

ERRORS         top

       No errors are defined.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       fpclassify(3p), isfinite(3p), isinf(3p), isnormal(3p),
       signbit(3p)

       The Base Definitions volume of POSIX.1‐2017, math.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 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 .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017                         ISNAN(3P)

Pages that refer to this page: math.h(0p),  acos(3p),  asin(3p),  atan2(3p),  atan(3p),  ceil(3p),  cos(3p),  cosh(3p),  erf(3p),  erfc(3p),  exp2(3p),  exp(3p),  fabs(3p),  floor(3p),  fmod(3p),  fpclassify(3p),  frexp(3p),  hypot(3p),  isfinite(3p),  isinf(3p),  isnormal(3p),  j0(3p),  ldexp(3p),  lgamma(3p),  log10(3p),  log(3p),  modf(3p),  pow(3p),  rint(3p),  signbit(3p),  sin(3p),  sinh(3p),  sqrt(3p),  tan(3p),  tanh(3p),  y0(3p)

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