1FABS(3) Linux Programmer's Manual FABS(3)
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6 fabs, fabsf, fabsl - absolute value of floating-point number
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9 #include <math.h>
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11 double fabs(double x);
12 float fabsf(float x);
13 long double fabsl(long double x);
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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 fabsf(), fabsl():
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 return the absolute value of the floating-point number
26 x.
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29 These functions return the absolute value of x.
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31 If x is a NaN, a NaN is returned.
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33 If x is -0, +0 is returned.
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35 If x is negative infinity or positive infinity, positive infinity is
36 returned.
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39 No errors occur.
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42 For an explanation of the terms used in this section, see at‐
43 tributes(7).
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45 ┌─────────────────────────┬───────────────┬─────────┐
46 │Interface │ Attribute │ Value │
47 ├─────────────────────────┼───────────────┼─────────┤
48 │fabs(), fabsf(), fabsl() │ 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 abs(3), cabs(3), ceil(3), floor(3), labs(3), rint(3)
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59 This page is part of release 5.10 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 FABS(3)