scalb(3) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | BUGS | SEE ALSO | COLOPHON

scalb(3)                Library Functions Manual                scalb(3)

NAME         top

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

LIBRARY         top

       Math library (libm, -lm)

SYNOPSIS         top

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

STANDARDS         top

       None.

HISTORY         top

       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         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 the man-pages (Linux kernel and C library
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       [email protected]

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

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