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)

Linux man-pages 6.7               2023-10-31                          scalb(3)