FMA(3M) | Mathematical Library Functions | FMA(3M) |

fma, fmaf, fmal - floating-point multiply-add

c99 [flag... ]file...-lm[library... ] #include <math.h>doublefma(doublex,doubley,doublez);

floatfmaf(floatx,floaty,floatz);

long doublefmal(long doublex,long doubley,long doublez);

These functions compute (*x* * *y*) + *z*, rounded
as one ternary operation. They compute the value (as if) to infinite
precision and round once to the result format, according to the rounding
mode characterized by the value of **FLT_ROUNDS**.

Upon successful completion, these functions return (*x* *
*y*) + *z*, rounded as one ternary operation.

If *x* or *y* are NaN, a NaN is returned.

If *x* multiplied by *y* is an exact infinity and
*z* is also an infinity but with the opposite sign, a domain error
occurs and a NaN is returned.

If one of *x* and *y* is infinite, the other is 0, and
*z* is not a NaN, a domain error occurs and a NaN is returned.

If *x***y* is not 0*Inf nor Inf*0 and *z* is a NaN,
a NaN is returned.

These functions will fail if:

**Domain Error**

The value of *x***y*+*z* is invalid or the
value *x***y* is invalid.

If the integer expression (**math_errhandling** &
**MATH_ERREXCEPT**) is non-zero, the invalid floating-point exception
will be raised.

**Range Error**

The result overflows.

If the integer expression (**math_errhandling** &
**MATH_ERREXCEPT**) is non-zero, the overflow floating-point exception
will be raised.

An application wanting to check for exceptions should call
**feclearexcept**(**FE_ALL_EXCEPT**) before calling these functions.
On return, if **fetestexcept**(**FE_INVALID** | **FE_DIVBYZERO** |
**FE_OVERFLOW** | **FE_UNDERFLOW**) is non-zero, an exception has been
raised. An application should either examine the return value or check the
floating point exception flags to detect exceptions.

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE | ATTRIBUTE VALUE |

Interface Stability | Standard |

MT-Level | MT-Safe |

math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), attributes(7), standards(7)

July 12, 2006 | SunOS 5.11 |