fma, fmaf, fmal - floating-point multiply and add
#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)):
These functions compute x
* y
+ z
. The
result is rounded as one ternary operation according to the current
rounding mode (see fenv(3)).
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.
See math_error(7) for information on how to determine whether an error has occurred when calling these functions.
The following errors can occur:
x
* y
+ z
, or x
*
y
is invalid and z
is not a NaNAn invalid floating-point exception (FE_INVALID) is raised.
An overflow floating-point exception (FE_OVERFLOW) is raised.
An underflow floating-point exception (FE_UNDERFLOW) is raised.
These functions do not set errno
.
These functions first appeared in glibc in version 2.1.
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
fma(), fmaf(), fmal() | Thread safety | MT-Safe |
C99, POSIX.1-2001, POSIX.1-2008.
This page is part of release 5.10 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/.