1FMA(3)                     Linux Programmer's Manual                    FMA(3)
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NAME

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

9       #include <math.h>
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11       double fma(double x, double y, double z);
12       float fmaf(float x, float y, float z);
13       long double fmal(long double x, long double y, long double z);
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15       Link with -lm.
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17   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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19       fma(), fmaf(), fmal():
20           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
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DESCRIPTION

23       These  functions  compute  x  *  y  +  z.  The result is rounded as one
24       ternary operation according to the current rounding mode (see fenv(3)).
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RETURN VALUE

27       These functions return the value of x * y + z, rounded as  one  ternary
28       operation.
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30       If x or y is a NaN, a NaN is returned.
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32       If  x times y is an exact infinity, and z is an infinity with the oppo‐
33       site sign, a domain error occurs, and a NaN is returned.
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35       If one of x or y is an infinity, the other is 0, and z is not a NaN,  a
36       domain error occurs, and a NaN is returned.
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38       If  one of x or y is an infinity, and the other is 0, and z is a NaN, a
39       domain error occurs, and a NaN is returned.
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41       If x times y is not an infinity times zero (or vice versa), and z is  a
42       NaN, a NaN is returned.
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44       If the result overflows, a range error occurs, and an infinity with the
45       correct sign is returned.
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47       If the result underflows, a range error occurs, and a signed 0  is  re‐
48       turned.
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ERRORS

51       See  math_error(7) for information on how to determine whether an error
52       has occurred when calling these functions.
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54       The following errors can occur:
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56       Domain error: x * y + z, or x * y is invalid and z is not a NaN
57              An invalid floating-point exception (FE_INVALID) is raised.
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59       Range error: result overflow
60              An overflow floating-point exception (FE_OVERFLOW) is raised.
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62       Range error: result underflow
63              An underflow floating-point exception (FE_UNDERFLOW) is raised.
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65       These functions do not set errno.
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VERSIONS

68       These functions first appeared in glibc in version 2.1.
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ATTRIBUTES

71       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
72       tributes(7).
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74       ┌──────────────────────┬───────────────┬─────────┐
75       │Interface             │ Attribute     │ Value   │
76       ├──────────────────────┼───────────────┼─────────┤
77       │fma(), fmaf(), fmal() │ Thread safety │ MT-Safe │
78       └──────────────────────┴───────────────┴─────────┘

CONFORMING TO

80       C99, POSIX.1-2001, POSIX.1-2008.
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SEE ALSO

83       remainder(3), remquo(3)
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COLOPHON

86       This  page  is  part of release 5.10 of the Linux man-pages project.  A
87       description of the project, information about reporting bugs,  and  the
88       latest     version     of     this    page,    can    be    found    at
89       https://www.kernel.org/doc/man-pages/.
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93                                  2017-09-15                            FMA(3)
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