# scalbln(3) — Linux manual page

```scalbln(3)              Library Functions Manual              scalbln(3)
```

## NAME         top

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

## LIBRARY         top

```       Math library (libm, -lm)
```

## SYNOPSIS         top

```       #include <math.h>

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

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

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         top

```       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         top

```       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         top

```       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         top

```       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         top

```       C11, POSIX.1-2008.
```

## HISTORY         top

```       glibc 2.1.  C99, POSIX.1-2001.
```

## HISTORY         top

```       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.
```

## NOTES         top

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

## BUGS         top

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

## SEE ALSO         top

```       ldexp(3), scalb(3)

Linux man-pages (unreleased)     (date)                       scalbln(3)
```

Pages that refer to this page: ldexp(3)scalb(3)