scalbln(3) — Linux manual page


scalbln(3)              Library Functions Manual              scalbln(3)

NAME         top

       scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl - multiply
       floating-point number by integral power of radix

LIBRARY         top

       Math library (libm, -lm)

SYNOPSIS         top

       #include <math.h>

       double scalbln(double x, long exp);
       float scalblnf(float x, long exp);
       long double scalblnl(long double x, long exp);

       double scalbn(double x, int exp);
       float scalbnf(float x, int exp);
       long double scalbnl(long double x, int exp);

   Feature Test Macro Requirements for glibc (see

       scalbln(), scalblnf(), scalblnl():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE

       scalbn(), scalbnf(), scalbnl():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* 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

RETURN VALUE         top

       On success, these functions return x * FLT_RADIX ** exp.

       If x is a NaN, a NaN is returned.

       If x is positive infinity (negative infinity), positive infinity
       (negative infinity) is returned.

       If x is +0 (-0), +0 (-0) 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:

       Range error, overflow
              An overflow floating-point exception (FE_OVERFLOW) is

       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
       │ Interface                           Attribute     Value   │
       │ scalbn(), scalbnf(), scalbnl(),     │ Thread safety │ MT-Safe │
       │ scalbln(), scalblnf(), scalblnl()   │               │         │

STANDARDS         top

       C11, POSIX.1-2008.

HISTORY         top

       glibc 2.1.  C99, POSIX.1-2001.

HISTORY         top

       These functions differ from the obsolete functions described in
       scalb(3) in the type of their second argument.  The functions
       described on this page have a second argument of an integral
       type, while those in scalb(3) have a second argument of type

NOTES         top

       If FLT_RADIX equals 2 (which is usual), then scalbn() is
       equivalent to ldexp(3).

BUGS         top

       Before glibc 2.20, these functions did not set errno for range

SEE ALSO         top

       ldexp(3), scalb(3)

Linux man-pages (unreleased)     (date)                       scalbln(3)

Pages that refer to this page: ldexp(3)scalb(3)