scalbln(3) Library Functions Manual scalbln(3) scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl - scale by an integer power of radix (libm, -lm) #include 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); glibc (. 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 || /* 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 FLT_RADIX . On success, these functions return x * FLT_RADIX ** e. x NaN, NaN. x , . x +0 (-0), +0 (-0). , HUGE_VAL, HUGE_VALF HUGE_VALL, , x. , , 0 x. math_error(7), , . : , (FE_OVERFLOW). , errno ERANGE. (FE_UNDERFLOW). attributes(7). +----------------------------+----------------------------------------------------------+--------------------------+ | | | | +----------------------------+----------------------------------------------------------+--------------------------+ |scalbn(), scalbnf(), | | MT-Safe | |scalbnl(), scalbln(), | | | |scalblnf(), scalblnl() | | | +----------------------------+----------------------------------------------------------+--------------------------+ C11, POSIX.1-2008. glibc 2.1. C99, POSIX.1-2001. , scalb(3), . , , , scalb(3) double. FLT_RADIX 2 (), scalbn() ldexp(3). Before glibc 2.20, these functions did not set errno for range errors. ldexp(3), scalb(3) () Alexander Golubev , Azamat Hackimov , Hotellook, Nikita , Spiros Georgaras , Vladislav , Yuri Kozlov , Kirill Rekhov ; GNU (GNU General Public License - GPL, 3 ) , - . - , , () () () <>. Linux 6.15 19 2025 . scalbln(3)