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)):

`_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L`

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:

- 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`

.

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.

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