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   scalbl    ( 3 )

умножить число с плавающей запятой на целую степень системы счисления (УСТАРЕЛО) (multiply floating-point number by integral power of radix (OBSOLETE))

Имя (Name)

scalb, scalbf, scalbl - multiply floating-point number by
       integral power of radix (OBSOLETE)

Синопсис (Synopsis)

#include <math.h>

double scalb(double x, double exp); float scalbf(float x, float exp); long double scalbl(long double x, long double exp);

Link with -lm.

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

scalb(): _XOPEN_SOURCE >= 500 || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

scalbf(), scalbl(): _XOPEN_SOURCE >= 600 || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE


Описание (Description)

These functions multiply their first argument x by FLT_RADIX
       (probably 2) to the power of exp, that is:

x * FLT_RADIX ** exp

The definition of FLT_RADIX can be obtained by including <float.h>.


Возвращаемое значение (Return value)

On success, these functions return x * FLT_RADIX ** exp.

If x or exp is a NaN, a NaN is returned.

If x is positive infinity (negative infinity), and exp is not negative infinity, positive infinity (negative infinity) is returned.

If x is +0 (-0), and exp is not positive infinity, +0 (-0) is returned.

If x is zero, and exp is positive infinity, a domain error occurs, and a NaN is returned.

If x is an infinity, and exp is negative infinity, a domain error occurs, and a NaN is returned.

If the result overflows, a range error occurs, and the functions return HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively, with a sign the same as x.

If the result underflows, a range error occurs, and the functions return zero, with a sign the same as x.


Ошибки (Error)

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, and exp is positive infinity, or x is positive infinity and exp is negative infinity and the other argument is not a NaN errno is set to EDOM. An invalid floating-point exception (FE_INVALID) is raised.

Range error, overflow errno is set to ERANGE. An overflow floating-point exception (FE_OVERFLOW) is raised.

Range error, underflow errno is set to ERANGE. An underflow floating-point exception (FE_UNDERFLOW) is raised.


Атрибуты (Attributes)

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

┌──────────────────────────────────────┬───────────────┬─────────┐ │Interface Attribute Value │ ├──────────────────────────────────────┼───────────────┼─────────┤ │scalb(), scalbf(), scalbl() │ Thread safety │ MT-Safe │ └──────────────────────────────────────┴───────────────┴─────────┘


Стандарты (Conforming to)

scalb() is specified in POSIX.1-2001, but marked obsolescent.
       POSIX.1-2008 removes the specification of scalb(), recommending
       the use of scalbln(3), scalblnf(3), or scalblnl(3) instead.  The
       scalb() function is from 4.3BSD.

scalbf() and scalbl() are unstandardized; scalbf() is nevertheless present on several other systems


Ошибки (баги) (Bugs)

Before glibc 2.20, these functions did not set errno for domain
       and range errors.

Смотри также (See also)

ldexp(3), scalbln(3)