# scalbln

## NAME



           scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl - scale by
           an integer power of radix
    


## LIBRARY



           Math library (_libm_ , _-lm_)
    


## SYNOPSIS



           **#include <math.h>**
    
           **double scalbln(double** _x_**, long** _e_**);**
           **float scalblnf(float** _x_**, long** _e_**);**
           **long double scalblnl(long double** _x_**, long** _e_**);**
    
           **double scalbn(double** _x_**, int** _e_**);**
           **float scalbnf(float** _x_**, int** _e_**);**
           **long double scalbnl(long double** _x_**, int** _e_**);**
    
       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 <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
    


## DESCRIPTION



           These functions multiply their first argument _x_ by **FLT_RADIX**
           (probably 2) to the power of _e_ , that is:
    
               x * FLT_RADIX ** e
    
           The definition of **FLT_RADIX** can be obtained by including
           _< float.h>_.
    


## RETURN VALUE



           On success, these functions return _x_ * **FLT_RADIX** ** _e_.
    
           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
                  _errno_ is set to **ERANGE**.  An underflow floating-point
                  exception (**FE_UNDERFLOW**) is raised.
    


## 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**()    │               │         │
           └──────────────────────────────────────┴───────────────┴─────────┘
    


## STANDARDS



           C11, POSIX.1-2008.
    


## NOTES



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


## BUGS



           Before glibc 2.20, these functions did not set _errno_ for range
           errors.
    


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