NAME

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

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

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 │
       └───────────────────────────────────────────────────────────────┴───────────────┴─────────┘

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

BUGS

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

SEE ALSO

       ldexp(3), scalbln(3)

COLOPHON

       This page is part of release 5.13 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at https://www.kernel.org/doc/man-pages/.

                                            2021-03-22                                   SCALB(3)