finite(3) - Linux manual page (original) (raw)

finite(3) Library Functions Manual finite(3)

NAME top

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

LIBRARY top

   Math library (_libm_, _-lm_)

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 >= 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 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)](../man7/attributes.7.html).
   ┌──────────────────────────────────────┬───────────────┬─────────┐
   │ **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)](../man3/fpclassify.3.html).

SEE ALSO top

   [fpclassify(3)](../man3/fpclassify.3.html)

COLOPHON top

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Linux man-pages 6.10 2024-07-23 finite(3)

Pages that refer to this page:fpclassify(3)