FMA(3)Linux Programmer's ManualFMA(3)NAME fma, fmaf, fmal - floating-point multiply and add SYNOPSIS #include <math.h> double fma(double x, double y, double z); float fmaf(float x, float y, float z); long double fmal(long double x, long double y, long double z); Link with -lm. Feature Test Macro Requirements for glibc (seefeature_test_macros(7)): fma(), fmaf(), fmal(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L DESCRIPTION These functions compute x * y + z. The result is rounded as one ternary operation according to the current rounding mode (seefenv(3)). RETURN VALUE These functions return the value of x * y + z, rounded as one ternary operation. If x or y is a NaN, a NaN is returned. If x times y is an exact infinity, and z is an infinity with the oppo- site sign, a domain error occurs, and a NaN is returned. If one of x or y is an infinity, the other is 0, and z is not a NaN, a domain error occurs, and a NaN is returned. If one of x or y is an infinity, and the other is 0, and z is a NaN, a domain error occurs, and a NaN is returned. If x times y is not an infinity times zero (or vice versa), and z is a NaN, a NaN is returned. If the result overflows, a range error occurs, and an infinity with the correct sign is returned. If the result underflows, a range error occurs, and a signed 0 is returned. ERRORS Seemath_error(7)for information on how to determine whether an error has occurred when calling these functions. The following errors can occur: Domain error: x * y + z, or x * y is invalid and z is not a NaN An invalid floating-point exception (FE_INVALID) is raised. Range error: result overflow An overflow floating-point exception (FE_OVERFLOW) is raised. Range error: result underflow An underflow floating-point exception (FE_UNDERFLOW) is raised. These functions do not set errno. VERSIONS These functions first appeared in glibc in version 2.1. ATTRIBUTES For an explanation of the terms used in this section, seeattributes(7). +----------------------+---------------+---------+ |Interface | Attribute | Value | +----------------------+---------------+---------+ |fma(), fmaf(), fmal() | Thread safety | MT-Safe | +----------------------+---------------+---------+ CONFORMING TO C99, POSIX.1-2001, POSIX.1-2008. SEE ALSOremainder(3),remquo(3)COLOPHON This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. 2017-09-15FMA(3)