modff(3) - f39

1modf(3)                    Library Functions Manual                    modf(3)
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NAME

6       modf, modff, modfl - extract signed integral and fractional values from
7       floating-point number
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LIBRARY

10       Math library (libm, -lm)
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SYNOPSIS

13       #include <math.h>
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15       double modf(double x, double *iptr);
16       float modff(float x, float *iptr);
17       long double modfl(long double x, long double *iptr);
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19   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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21       modff(), modfl():
22           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
23               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
24               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

27       These functions break the argument x into an integral part and a  frac‐
28       tional  part,  each of which has the same sign as x.  The integral part
29       is stored in the location pointed to by iptr.
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RETURN VALUE

32       These functions return the fractional part of x.
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34       If x is a NaN, a NaN is returned, and *iptr is set to a NaN.
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36       If x is positive infinity (negative infinity), +0 (-0) is returned, and
37       *iptr is set to positive infinity (negative infinity).
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ERRORS

40       No errors occur.
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ATTRIBUTES

43       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
44       tributes(7).
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46       ┌────────────────────────────────────────────┬───────────────┬─────────┐
47       │Interface                                   │ Attribute     │ Value   │
48       ├────────────────────────────────────────────┼───────────────┼─────────┤
49       │modf(), modff(), modfl()                    │ Thread safety │ MT-Safe │
50       └────────────────────────────────────────────┴───────────────┴─────────┘
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STANDARDS

53       C11, POSIX.1-2008.
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HISTORY

56       C99, POSIX.1-2001.
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58       The variant returning double also conforms to SVr4, 4.3BSD, C89.
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