scalb(3) — Linux manual page

scalb(3)                Library Functions Manual                scalb(3)

NAME

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

LIBRARY

       Math library (libm, -lm)

SYNOPSIS

       #include <math.h>

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

   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

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>.

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.

ERRORS

       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.

ATTRIBUTES

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

STANDARDS

       None.

HISTORY

       scalb()
              4.3BSD.  Obsolescent in POSIX.1-2001; Removed in
              POSIX.1-2008, recommending the use of scalbln(3),
              scalblnf(3), or scalblnl(3) instead.

BUGS

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

SEE ALSO

       ldexp(3), scalbln(3)

COLOPHON

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

Pages that refer to this page: scalbln(3), significand(3)

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