FMA(3)							     Linux Programmer's Manual							    FMA(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 (see feature_test_macros(7)):

       fma(), fmaf(), fmal(): _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION

       The  fma()  function  computes  x  *  y	+  z.	The result is rounded as one ternary operation according to the current rounding mode (see
       fenv(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 opposite 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

       See math_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.

CONFORMING TO

       C99, POSIX.1-2001.

SEE ALSO

       remainder(3), remquo(3)

COLOPHON

       This page is part of release 3.25 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

								    2008-10-06								    FMA(3)