FMA
Section: Linux Programmer's Manual (3)
Updated: 2017-09-15
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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():
-
_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 (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.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
fma(),
fmaf(),
fmal()
| Thread safety | MT-Safe
|
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
SEE ALSO
remainder(3),
remquo(3)
COLOPHON
This page is part of release 4.13 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- VERSIONS
-
- ATTRIBUTES
-
- CONFORMING TO
-
- SEE ALSO
-
- COLOPHON
-
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