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           _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
21           _POSIX_C_SOURCE >= 200112L;
22           or cc -std=c99
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DESCRIPTION

25       The fma() function computes x * y + z.  The result is  rounded  as  one
26       ternary operation according to the current rounding mode (see fenv(3)).
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RETURN VALUE

29       These  functions  return the value of x * y + z, rounded as one ternary
30       operation.
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32       If x or y is a NaN, a NaN is returned.
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34       If x times y is an exact infinity, and z is an infinity with the  oppo‐
35       site sign, a domain error occurs, and a NaN is returned.
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37       If  one of x or y is an infinity, the other is 0, and z is not a NaN, a
38       domain error occurs, and a NaN is returned.
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40       If one of x or y is an infinity, and the other is 0, and z is a NaN,  a
41       domain error occurs, and a NaN is returned.
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43       If  x times y is not an infinity times zero (or vice versa), and z is a
44       NaN, a NaN is returned.
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46       If the result overflows, a range error occurs, and an infinity with the
47       correct sign is returned.
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49       If  the  result  underflows,  a  range  error occurs, and a signed 0 is
50       returned.
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ERRORS

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

70       These functions first appeared in glibc in version 2.1.
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CONFORMING TO

73       C99, POSIX.1-2001.
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SEE ALSO

76       remainder(3), remquo(3)
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COLOPHON

79       This  page  is  part of release 3.53 of the Linux man-pages project.  A
80       description of the project, and information about reporting  bugs,  can
81       be found at http://www.kernel.org/doc/man-pages/.
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85                                  2010-09-20                            FMA(3)
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