ilogb(3) — Справочная страница Linux

ilogb(3)                Library Functions Manual                ilogb(3)

ИМЯ

       ilogb, ilogbf, ilogbl - get integer exponent of a floating-point
       value

БИБЛИОТЕКА

       Math library (libm, -lm)

СИНТАКСИС

       #include <math.h>

       int ilogb(double x);
       int ilogbf(float x);
       int ilogbl(long double x);

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

       ilogb():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || _XOPEN_SOURCE >= 500
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

       ilogbf(), ilogbl():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

ОПИСАНИЕ

       These functions return the exponent part of their argument as a
       signed integer.  When no error occurs, these functions are
       equivalent to the corresponding logb(3) functions, cast to int.

ЗНАЧЕНИЕ, ВОЗВРАЩАЕМОЕ ФУНКЦИЕЙ

       On success, these functions return the exponent of x, as a signed
       integer.

       If x is zero, then a domain error occurs, and the functions
       return FP_ILOGB0.

       If x is a NaN, then a domain error occurs, and the functions
       return FP_ILOGBNAN.

       If x is negative infinity or positive infinity, then a domain
       error occurs, and the functions return INT_MAX.

ОШИБКИ

       See math_error(7) for information on how to determine whether an
       error has occurred when calling these functions.

       The following errors can occur:

       Domain error: x is 0 or a NaN
              An invalid floating-point exception (FE_INVALID) is
              raised, and errno is set to EDOM (but see BUGS).

       Domain error: x is an infinity
              An invalid floating-point exception (FE_INVALID) is
              raised, and errno is set to EDOM (but see BUGS).

АТРИБУТЫ

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌─────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                           │ Attribute     │ Value   │
       ├─────────────────────────────────────┼───────────────┼─────────┤
       │ ilogb(), ilogbf(), ilogbl()         │ Thread safety │ MT-Safe │
       └─────────────────────────────────────┴───────────────┴─────────┘

СТАНДАРТЫ

       C11, POSIX.1-2008.

ИСТОРИЯ

       C99, POSIX.1-2001.

НЕДОСТАТКИ

       Before glibc 2.16, the following bugs existed in the glibc
       implementation of these functions:

       •  The domain error case where x is 0 or a NaN did not cause
          errno to be set or (on some architectures) raise a floating-
          point exception.

       •  The domain error case where x is an infinity did not cause
          errno to be set or raise a floating-point exception.

СМОТРИТЕ ТАКЖЕ

       log(3), logb(3), significand(3)

КОЛОФОН

       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.9.1.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2024-06-26.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       man-pages@man7.org

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

Страницы, ссылающиеся на эту: logb(3), significand(3)