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man:scalbf

SCALB(3) Linux Programmer's Manual SCALB(3)

NAME

```     scalb,  scalbf,  scalbl  -  multiply  floating-point number by integral

SYNOPSIS

`     #include <math.h>`
```     double scalb(double x, double exp);
float scalbf(float x, float exp);
long double scalbl(long double x, long double exp);```
`     Link with -lm.`
` Feature Test Macro Requirements for glibc (see feature_test_macros(7)):`
```     scalb():
_XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
scalbf(), scalbl():
_XOPEN_SOURCE >= 600
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE```

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.```
`     These functions do not set errno.`

ATTRIBUTES

```     For  an  explanation  of  the  terms  used   in   this   section,   see
attributes(7).```
```     allbox;  lbw28  lb  lb  l  l  l.  Interface Attribute Value T{ scalb(),
scalbf(), scalbl() T}   Thread safety  MT-Safe```

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()  func-
tion is from 4.3BSD.```
```     scalbf()  and  scalbl()  are  unstandardized;  scalbf() is nevertheless
present on several other systems```

`     ldexp(3), scalbln(3)`
```     This page is part of release 4.16 of the Linux  man-pages  project.   A
`                                2017-09-15                          SCALB(3)`