scalb(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | BUGS | SEE ALSO | COLOPHON

SCALB(3)                  Linux Programmer's Manual                 SCALB(3)

NAME         top

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

SYNOPSIS         top

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

DESCRIPTION         top

       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         top

       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         top

       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         top

       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         top

       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         top

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

SEE ALSO         top

       ldexp(3), scalbln(3)

COLOPHON         top

       This page is part of release 5.08 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/.

                                 2020-06-09                         SCALB(3)

Pages that refer to this page: scalbln(3)scalblnf(3)scalblnl(3)scalbn(3)scalbnf(3)scalbnl(3)significand(3)significandf(3)significandl(3)