1MODF(3) Linux Programmer's Manual MODF(3)
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6 modf, modff, modfl - extract signed integral and fractional values from
7 floating-point number
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10 #include <math.h>
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12 double modf(double x, double *iptr);
13 float modff(float x, float *iptr);
14 long double modfl(long double x, long double *iptr);
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16 Link with -lm.
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18 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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20 modf(), modfl():
21 _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
22 || /* Since glibc 2.19: */ _DEFAULT_SOURCE
23 || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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26 These functions break the argument x into an integral part and a frac‐
27 tional part, each of which has the same sign as x. The integral part
28 is stored in the location pointed to by iptr.
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31 These functions return the fractional part of x.
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33 If x is a NaN, a NaN is returned, and *iptr is set to a NaN.
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35 If x is positive infinity (negative infinity), +0 (-0) is returned, and
36 *iptr is set to positive infinity (negative infinity).
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39 No errors occur.
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42 For an explanation of the terms used in this section, see
43 attributes(7).
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45 ┌─────────────────────────┬───────────────┬─────────┐
46 │Interface │ Attribute │ Value │
47 ├─────────────────────────┼───────────────┼─────────┤
48 │modf(), modff(), modfl() │ Thread safety │ MT-Safe │
49 └─────────────────────────┴───────────────┴─────────┘
51 C99, POSIX.1-2001, POSIX.1-2008.
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53 The variant returning double also conforms to SVr4, 4.3BSD, C89.
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56 frexp(3), ldexp(3)
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59 This page is part of release 4.16 of the Linux man-pages project. A
60 description of the project, information about reporting bugs, and the
61 latest version of this page, can be found at
62 https://www.kernel.org/doc/man-pages/.
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66 2017-09-15 MODF(3)