NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | ATTRIBUTES | CONFORMING TO | SEE ALSO | COLOPHON

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

NAME         top

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

SYNOPSIS         top

       #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         top

       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         top

       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.

ERRORS         top

       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         top

       These functions first appeared in glibc in version 2.1.

ATTRIBUTES         top

       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         top

       C99, POSIX.1-2001, POSIX.1-2008.

SEE ALSO         top

       remainder(3), remquo(3)

COLOPHON         top

       This page is part of release 4.08 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/.

                                 2016-03-15                           FMA(3)