modf(3) Library Functions Manual modf(3) modf, modff, modfl - (libm, -lm) #include double modf(double x, double *iptr); float modff(float x, float *iptr); long double modfl(long double x, long double *iptr); glibc (. feature_test_macros(7)): modff(), modfl(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE x , , x. , iptr. x. x NaN, NaN *iptr NaN. x , +0 (-0) *iptr . . attributes(7). +----------------------------+----------------------------------------------------------+--------------------------+ | | | | +----------------------------+----------------------------------------------------------+--------------------------+ |modf(), modff(), modfl() | | MT-Safe | +----------------------------+----------------------------------------------------------+--------------------------+ C11, POSIX.1-2008. C99, POSIX.1-2001. , double, SVr4, 4.3BSD, C89. frexp(3), ldexp(3) () aereiae , Alexey , Azamat Hackimov , Dmitriy S. Seregin , Dmitry Bolkhovskikh , ITriskTI , Max Is , Yuri Kozlov , ; GNU (GNU General Public License - GPL, 3 ) , - . - , , () () () . Linux man-pages 6.18 8 2026 . modf(3)