scalbln(3) - Linux manual page (original) (raw)

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)](../man7/math%5Ferror.7.html) 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](../man3/errno.3.html)_ 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)](../man7/attributes.7.html).
   ┌──────────────────────────────────────┬───────────────┬─────────┐
   │ **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)](../man3/scalb.3.html) 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)](../man3/scalb.3.html) have a second argument of type _double_.

NOTES top

   If **FLT_RADIX** equals 2 (which is usual), then **scalbn**() is
   equivalent to [ldexp(3)](../man3/ldexp.3.html).

BUGS top

   Before glibc 2.20, these functions did not set _[errno](../man3/errno.3.html)_ for range
   errors.

SEE ALSO top

   [ldexp(3)](../man3/ldexp.3.html), [scalb(3)](../man3/scalb.3.html)

COLOPHON top

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Linux man-pages 6.10 2024-07-23 scalbln(3)

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