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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | HISTORY | NOTES | BUGS | SEE ALSO | COLOPHON |
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scalbln(3) Library Functions Manual scalbln(3)
scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl - scale by
an integer power of radix
Math library (libm, -lm)
#include <math.h>
double scalbln(double x, long e);
float scalblnf(float x, long e);
long double scalblnl(long double x, long e);
double scalbn(double x, int e);
float scalbnf(float x, int e);
long double scalbnl(long double x, int e);
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
These functions multiply their first argument x by FLT_RADIX
(probably 2) to the power of e, that is:
x * FLT_RADIX ** e
The definition of FLT_RADIX can be obtained by including
<float.h>.
On success, these functions return x * FLT_RADIX ** e.
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.
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.
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() │ │ │
└──────────────────────────────────────┴───────────────┴─────────┘
C11, POSIX.1-2008.
glibc 2.1. C99, POSIX.1-2001.
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.
If FLT_RADIX equals 2 (which is usual), then scalbn() is
equivalent to ldexp(3).
Before glibc 2.20, these functions did not set errno for range
errors.
ldexp(3), scalb(3)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-07-19 scalbln(3)
Pages that refer to this page: ldexp(3), scalb(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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