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(), | | MT-Safe | |truncf(), | | | |truncl() | | | +------------+------------------------------------+--------------------+ 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) 3 . . : . 6.18 8 2026 trunc(3)