Manual Reference Pages - FMA (3)
NAME
fma, fmaf, fmal - floating-point multiply and add
CONTENTS
Synopsis
Description
Return Value
Errors
Versions
Colophon
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 ||
_POSIX_C_SOURCE >= 200112L;
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
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man-pages project.
A description of the project,
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