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SCALBN(3) |
Library Functions Manual |
SCALBN(3) |
NAME
scalbn, scalbnf, scalbnl — exponent 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 following may occur:
-
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.
-
When the correct value would cause an underflow and it is not representable, a range error occurs and either 0.0 or an implementation-defined value is returned. When an underflow occurs but the correct value is representable, a range error occurs but the correct value is returned.
-
If x is ±0 or ±Inf, x is returned. Likewise, if n is zero, x is returned. If x is NaN, NaN is returned.
STANDARDS
The described functions conform to ISO/IEC 9899:1999 (“ISO C99”).