scalbn(3)

NAME

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

SYNOPSIS

   #include <math.h>

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

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

   Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

   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 versions <= 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 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

   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 raised.

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

   These functions do not set errno.

VERSIONS

   These functions first appeared in glibc in version 2.1.

ATTRIBUTES

   For  an  explanation  of  the  terms  used   in   this   section,   see
   attributes(7).

   ┌──────────────────────────────────┬───────────────┬─────────┐
   │Interface                         │ Attribute     │ Value   │
   ├──────────────────────────────────┼───────────────┼─────────┤
   │scalbn(), scalbnf(), scalbnl(),   │ Thread safety │ MT-Safe │
   │scalbln(), scalblnf(), scalblnl() │               │         │
   └──────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

   C99, POSIX.1-2001, POSIX.1-2008.

NOTES

   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 double.

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

SEE ALSO

   ldexp(3), scalb(3)

COLOPHON

   This  page  is  part of release 4.09 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/.

                              2016-03-15                        SCALBLN(3)

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