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**NAME**

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

**SYNOPSIS**

#include<math.h>doublefma(doublex,doubley,doublez);floatfmaf(floatx,floaty,floatz);longdoublefmal(longdoublex,longdoubley,longdoublez);Link with-lm. Feature Test Macro Requirements for glibc (seefeature_test_macros(7)):fma(),fmaf(),fmal(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

**DESCRIPTION**

These functions computex*y+z. The result is rounded as one ternary operation according to the current rounding mode (seefenv(3)).

**RETURN** **VALUE**

These functions return the value ofx*y+z, rounded as one ternary operation. Ifxoryis a NaN, a NaN is returned. Ifxtimesyis an exact infinity, andzis an infinity with the opposite sign, a domain error occurs, and a NaN is returned. If one ofxoryis an infinity, the other is 0, andzis not a NaN, a domain error occurs, and a NaN is returned. If one ofxoryis an infinity, and the other is 0, andzis a NaN, a domain error occurs, and a NaN is returned. Ifxtimesyis not an infinity times zero (or vice versa), andzis 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**

Seemath_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, orx*yis invalid andzis 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 seterrno.

**VERSIONS**

These functions first appeared in glibc in version 2.1.

**ATTRIBUTES**

For an explanation of the terms used in this section, seeattributes(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 5.02 of the Linuxman-pagesproject. 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/. 2017-09-15 FMA(3)