1FMOD(3) Linux Programmer's Manual FMOD(3)
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6 fmod, fmodf, fmodl - floating-point remainder function
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9 #include <math.h>
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11 double fmod(double x, double y);
12 float fmodf(float x, float y);
13 long double fmodl(long double x, long double y);
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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 fmodf(), fmodl():
20 _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
21 || /* Since glibc 2.19: */ _DEFAULT_SOURCE
22 || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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25 These functions compute the floating-point remainder of dividing x by
26 y. The return value is x - n * y, where n is the quotient of x / y,
27 rounded toward zero to an integer.
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30 On success, these functions return the value x - n*y, for some integer
31 n, such that the returned value has the same sign as x and a magnitude
32 less than the magnitude of y.
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34 If x or y is a NaN, a NaN is returned.
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36 If x is an infinity, a domain error occurs, and a NaN is returned.
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38 If y is zero, a domain error occurs, and a NaN is returned.
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40 If x is +0 (-0), and y is not zero, +0 (-0) is returned.
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43 See math_error(7) for information on how to determine whether an error
44 has occurred when calling these functions.
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46 The following errors can occur:
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48 Domain error: x is an infinity
49 errno is set to EDOM (but see BUGS). An invalid floating-point
50 exception (FE_INVALID) is raised.
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52 Domain error: y is zero
53 errno is set to EDOM. An invalid floating-point exception
54 (FE_INVALID) is raised.
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57 For an explanation of the terms used in this section, see at‐
58 tributes(7).
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60 ┌─────────────────────────┬───────────────┬─────────┐
61 │Interface │ Attribute │ Value │
62 ├─────────────────────────┼───────────────┼─────────┤
63 │fmod(), fmodf(), fmodl() │ Thread safety │ MT-Safe │
64 └─────────────────────────┴───────────────┴─────────┘
66 C99, POSIX.1-2001, POSIX.1-2008.
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68 The variant returning double also conforms to SVr4, 4.3BSD, C89.
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71 Before version 2.10, the glibc implementation did not set errno to EDOM
72 when a domain error occurred for an infinite x.
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75 remainder(3)
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78 This page is part of release 5.10 of the Linux man-pages project. A
79 description of the project, information about reporting bugs, and the
80 latest version of this page, can be found at
81 https://www.kernel.org/doc/man-pages/.
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85 2017-09-15 FMOD(3)