fabs(3) Library Functions Manual fabs(3) fabs, fabsf, fabsl - (libm -lm) #include double fabs(double x); float fabsf(float x); long double fabsl(long double x); glibc ( feature_test_macros(7)): fabsf(), fabsl(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE x. x. x (NaN) NaN. x -0 +0. x . . attributes(7). +------------+------------------------------------+--------------------+ || | | +------------+------------------------------------+--------------------+ |fabs(), | | MT-Safe | |fabsf(), | | | |fabsl() | | | +------------+------------------------------------+--------------------+ C11, POSIX.1-2008. C99 POSIX.1-2001. double SVr4 4.3BSD C89. abs(3), cabs(3), ceil(3), floor(3), labs(3), rint(3) 3 . . : . 6.18 8 2026 fabs(3)