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NAME |LIBRARY |SYNOPSIS |DESCRIPTION |RETURN VALUE |ERRORS |ATTRIBUTES |STANDARDS |HISTORY |HISTORY |NOTES |BUGS |SEE ALSO |COLOPHON | |
scalbln(3) Library Functions Manualscalbln(3)scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl - scale by an integer power of radix
Math library (libm,-lm)
#include <math.h>double scalbln(doublex, longe);float scalblnf(floatx, longe);long double scalblnl(long doublex, longe);double scalbn(doublex, inte);float scalbnf(floatx, inte);long double scalbnl(long doublex, inte); Feature Test Macro Requirements for glibc (seefeature_test_macros(7)):scalbln(),scalblnf(),scalblnl(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCEscalbn(),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 argumentx byFLT_RADIX (probably 2) to the power ofe, that is: x * FLT_RADIX ** e The definition ofFLT_RADIXcan be obtained by including<float.h>.
On success, these functions returnx *FLT_RADIX**e. Ifx is a NaN, a NaN is returned. Ifx is positive infinity (negative infinity), positive infinity (negative infinity) is returned. Ifx is +0 (-0), +0 (-0) is returned. If the result overflows, a range error occurs, and the functions returnHUGE_VAL,HUGE_VALF, orHUGE_VALL, respectively, with a sign the same asx. If the result underflows, a range error occurs, and the functions return zero, with a sign the same asx.
Seemath_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, underflowerrno is set toERANGE. An underflow floating-point exception (FE_UNDERFLOW) is raised.
For an explanation of the terms used in this section, seeattributes(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 inscalb(3) in the type of their second argument. The functions described on this page have a second argument of an integral type, while those inscalb(3) have a second argument of typedouble.
IfFLT_RADIXequals 2 (which is usual), thenscalbn() is equivalent toldexp(3).
Before glibc 2.20, these functions did not seterrno for range errors.
ldexp(3),scalb(3)
This page is part of theman-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 isnot part of the original manual page), send a mail to man-pages@man7.orgLinux man-pages 6.15 2025-07-19scalbln(3)Pages that refer to this page:ldexp(3), scalb(3)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |