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



NAME
       scalb,  scalbf,  scalbl - multiply floating-point number by integral power of radix (OBSO‐
       LETE)

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():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
           _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
       scalbf(), scalbl():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600

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
              An invalid floating-point exception (FE_INVALID) is raised.

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

       Range error, underflow
              An underflow floating-point exception (FE_UNDERFLOW) is raised.

       These functions do not set errno.

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

SEE ALSO
       ldexp(3), scalbln(3)

COLOPHON
       This  page  is  part of release 3.74 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 http://www.kernel.org/doc/man-pages/.



                                            2013-03-23                                   SCALB(3)