finite(3) — Linux manual page

finite(3)               Library Functions Manual               finite(3)

NAME

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

LIBRARY

       Math library (libm, -lm)

SYNOPSIS

       #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 >= 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

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

       isinff(), isinfl():
           /* glibc >= 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

       isnan():
           _XOPEN_SOURCE || _ISOC99_SOURCE
               || /* glibc >= 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

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

DESCRIPTION

       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

       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

       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

       fpclassify(3)

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                      finite(3)

Pages that refer to this page: fpclassify(3)

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