# fmaf(3) [opendarwin man page]

FMA(3) BSD Library Functions Manual FMA(3)NAME

fmamultiply and add, then round--SYNOPSIS

#include <math.h> double fma(double x, double y, double z); float fmaf(float x, float y, double z);DESCRIPTION

The fma() and fmaf() functions compute (x*y)+z, rounded as one ternary operation: they compute the value (as if) to infinite precision and round once to the result format, according to the current rounding mode.SPECIAL VALUES

fma(x, y, z) returns a NaN and optionally raises the "invalid" floating-point exception if one of x and y is infinite, the other is 0, and z is a NaN. fma(x, y, z) returns a NaN and raises the "invalid" floating-point exception if one of x and y is infinite, the other is 0, and z is not NaN. fma(x, y, z) returns a NaN and raises the "invalid" floating-point exception if x times y is an exact infinity, and z is also an infinity but with the opposite sign.SEE ALSO

fdim(3), fmax(3), fmin(3)STANDARDS

The fma() and fmaf() functions conform to ISO/IEC 9899:1999(E).BSD

July 24, 2003 BSD

## Check Out this Related Man Page

fma(3M) Mathematical Library Functions fma(3M)NAME

fma, fmaf, fmal - floating-point multiply-addSYNOPSIS

cc [ flag... ] file...[ library... ] #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);-lmDESCRIPTION

These functions compute (x * y) + z, rounded as one ternary operation. They compute the value (as if) to infinite precision and round once to the result format, according to the rounding mode characterized by the value of FLT_ROUNDS.RETURN VALUES

Upon successful completion, these functions return (x * y) + z, rounded as one ternary operation. If x or y are NaN, a NaN is returned. If x multiplied by y is an exact infinity and z is also an infinity but with the opposite sign, a domain error occurs and a NaN is returned. If one of x and y is infinite, the other is 0, and z is not a NaN, a domain error occurs and a NaN is returned. If x*y is not 0*Inf nor Inf*0 and z is a NaN, a NaN is returned.ERRORS

These functions will fail if: Domain Error The value of x*y+z is invalid or the value x*y is invalid. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the invalid floating-point exception will be raised. Range Error The result overflows. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the overflow floating-point exception will be raised.USAGE

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.ATTRIBUTES

See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+SEE ALSO

feclearexcept(3M), fetestexcept(3M), math.h(3HEAD), attributes(5), standards(5)SunOS 5.1020 Sep 2004 fma(3M)