finite(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | ATTRIBUTES | NOTES | SEE ALSO | COLOPHON

FINITE(3)               Linux Programmer's Manual              FINITE(3)

NAME         top

       finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf,
       isnanl - BSD floating-point classification functions

SYNOPSIS         top

       #include <math.h>

       int finite(double x);
       int finitef(float x);
       int finitel(long double x);

       int isinf(double x);
       int isinff(float x);
       int isinfl(long double x);

       int isnan(double x);
       int isnanf(float x);
       int isnanl(long double x);

   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):

       finite(), finitef(), finitel():
           /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

       isinf():
           _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE
               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

       isinff(), isinfl():
           /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

       isnan():
           _XOPEN_SOURCE || _ISOC99_SOURCE
               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

       isnanf(), isnanl():
           _XOPEN_SOURCE >= 600
               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION         top

       The finite(), finitef(), and finitel() functions return a nonzero
       value if x is neither infinite nor a "not-a-number" (NaN) value,
       and 0 otherwise.

       The isnan(), isnanf(), and isnanl() functions return a nonzero
       value if x is a NaN value, and 0 otherwise.

       The isinf(), isinff(), and isinfl() functions return 1 if x is
       positive infinity, -1 if x is negative infinity, and 0 otherwise.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).

       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │Interface                             Attribute     Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │finite(), finitef(), finitel(),       │ Thread safety │ MT-Safe │
       │isinf(), isinff(), isinfl(), isnan(), │               │         │
       │isnanf(), isnanl()                    │               │         │
       └──────────────────────────────────────┴───────────────┴─────────┘

NOTES         top

       Note that these functions are obsolete.  C99 defines macros
       isfinite(), isinf(), and isnan() (for all types) replacing them.
       Further note that the C99 isinf() has weaker guarantees on the
       return value.  See fpclassify(3).

SEE ALSO         top

       fpclassify(3)

COLOPHON         top

       This page is part of release 5.13 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

                               2021-03-22                      FINITE(3)

Pages that refer to this page: fpclassify(3)