# scalbn(3) [netbsd man page]

SCALBN(3) BSD Library Functions Manual SCALBN(3)NAME

scalbn, scalbnf, scalbnlexponent using FLT_RADIX--LIBRARY

Math Library (libm, -lm)SYNOPSIS

#include <math.h> double scalbn(double x, int n); float scalbnf(float x, int n); long double scalbnl(long double x, int n);DESCRIPTION

The scalbn(), scalbnf(), and scalbnl() functions compute x * r^n, where r is the radix of the machine's floating point arithmetic, defined by the FLT_RADIX constant in <float.h>. The rationale is efficiency; r^n is not computed explicitly.RETURN VALUES

As described above, upon successful completion, the described functions return the exponent computed using FLT_RADIX. Otherwise the follow- ing may occur: 1. When the result would cause an overflow, a range error occurs and +-HUGE_VAL, +-HUGE_VALF, or +-HUGE_VALL is returned according to the sign of x and the return type of the corresponding function. 2. When the correct value would cause an underflow and it is not representable, a range error occurs and either 0.0 or an implementa- tion-defined value is returned. When an underflow occurs but the correct value is representable, a range error occurs but the correct value is returned. 3. If x is +-0 or +-Inf, x is returned. Likewise, if n is zero, x is returned. If x is NaN, NaN is returned.SEE ALSO

exp(3), frexp(3), ldexp(3), math(3)STANDARDS

The described functions conform to ISO/IEC 9899:1999 (``ISO C99'').BSD

September 18, 2011 BSD

## Check Out this Related Man Page

scalbln(3M) Mathematical Library Functions scalbln(3M)NAME

scalbln, scalblnf, scalblnl, scalbn, scalbnf, scalbnl - compute exponent using FLT_RADIXSYNOPSIS

cc [ flag... ] file...[ library... ] #include <math.h> double scalbln(double x, long n); float scalblnf(float x, long n); long double scalblnl(long double x, long n); double scalbn(double x, int n); float scalbnf(float x, int n); long double scalbnl(long double x, int n);-lmDESCRIPTION

These functions compute x * FLT_RADIX**n efficiently, not normally by computing FLT_RADIX**n explicitly.RETURN VALUES

Upon successful completion, these functions return x * FLT_RADIX**n. If the result would cause overflow, a range error occurs and these functions return +-HUGE_VAL, +-HUGE_VALF, and +-HUGE_VALL (according to the sign of x) as appropriate for the return type of the function. If x is NaN, a NaN is returned. If x is +-0 or +-Inf, x is returned. If x is 0, x is returned.ERRORS

These functions will fail if: Range Error The result overflows. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception is raised.USAGE

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.ATTRIBUTES

See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+SEE ALSO

feclearexcept(3M), fetestexcept(3M), math.h(3HEAD), scalb(3M), attributes(5), standards(5)SunOS 5.101 Sep 2002 scalbln(3M)