trunc(3) Library Functions Manual trunc(3) trunc, truncf, truncl - (libm, -lm) #include double trunc(double x); float truncf(float x); long double truncl(long double x); glibc (. feature_test_macros(7)): trunc(), truncf(), truncl(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L x , x . . x , NaN, x. . attributes(7). +----------------------------+----------------------------------------------------------+--------------------------+ | | | | +----------------------------+----------------------------------------------------------+--------------------------+ |trunc(), truncf(), truncl() | | MT-Safe | +----------------------------+----------------------------------------------------------+--------------------------+ C11, POSIX.1-2008. glibc 2.1. C99, POSIX.1-2001. , , (int, long ). , , , . ceil(3), floor(3), lrint(3), nearbyint(3), rint(3), round(3) () Azamat Hackimov , Dmitry Bolkhovskikh , Yuri Kozlov ; GNU (GNU General Public License - GPL, 3 ) , - . - , , () () () . Linux man-pages 6.18 8 2026 . trunc(3)