FMA(3)                     Linux Programmer's Manual                    FMA(3)



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  oppo-
       site 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 4.16 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/.



                                  2017-09-15                            FMA(3)