### NAME

scalb, scalbf, scalbl - multiply floating-point number by integral power of radix (OBSOLETE)

### SYNOPSIS

**#include <math.h>**

**double scalb(double ***x***, double ***exp***);** **float scalbf(float ***x***, double ***exp***);** **long double scalbl(long double ***x***, double ***exp***);**

Link with *-lm*.

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

**scalb**(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500
**scalbf**(), **scalbl**(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600

### 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* or
*exp* is a NaN, a NaN is returned.

If
*x* is positive infinity (negative infinity),
and
*exp* is not negative infinity,
positive infinity (negative infinity) is returned.

If
*x* is +0 (-0), and
*exp* is not positive infinity, +0 (-0) is returned.

If
*x* is zero, and
*exp* is positive infinity,
a domain error occurs, and
a NaN is returned.

If
*x* is an infinity,
and
*exp* is negative infinity,
a domain error occurs, and
a NaN 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:

Domain error: x is 0, and exp is positive infinity,
| |

or x is positive infinity and exp is negative infinity
and the other argument is not a NaN
An invalid floating-point exception
(FE_INVALID) is raised.
| |

Range error, overflow | |

An overflow floating-point exception
(FE_OVERFLOW) is raised.
| |

Range error, underflow | |

An underflow floating-point exception
(FE_UNDERFLOW) is raised.
| |

*errno*.

### CONFORMING TO

**scalb**() is specified in POSIX.1-2001, but marked obsolescent.
POSIX.1-2008 removes the specification of
**scalb**(), recommending the use of
scalbln(3),
scalblnf(3),
or
scalblnl(3)
instead.
The
**scalb**() function is from 4.3BSD.

**scalbf**() and
**scalbl**() are unstandardized;
**scalbf**() is nevertheless present on several other systems

### SEE ALSO

### COLOPHON

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