1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
3 .\" %%%LICENSE_START(VERBATIM)
4 .\" Permission is granted to make and distribute verbatim copies of this
5 .\" manual provided the copyright notice and this permission notice are
6 .\" preserved on all copies.
8 .\" Permission is granted to copy and distribute modified versions of this
9 .\" manual under the conditions for verbatim copying, provided that the
10 .\" entire resulting derived work is distributed under the terms of a
11 .\" permission notice identical to this one.
13 .\" Since the Linux kernel and libraries are constantly changing, this
14 .\" manual page may be incorrect or out-of-date. The author(s) assume no
15 .\" responsibility for errors or omissions, or for damages resulting from
16 .\" the use of the information contained herein. The author(s) may not
17 .\" have taken the same level of care in the production of this manual,
18 .\" which is licensed free of charge, as they might when working
21 .\" Formatted or processed versions of this manual, if unaccompanied by
22 .\" the source, must acknowledge the copyright and authors of this work.
25 .\" References consulted:
26 .\" Linux libc source code
27 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
29 .\" Modified Sat Jul 24 19:42:04 1993 by Rik Faith (faith@cs.unc.edu)
30 .\" Added fabsl, fabsf, aeb, 2001-06-07
32 .TH FABS 3 2021-03-22 "" "Linux Programmer's Manual"
34 fabs, fabsf, fabsl \- absolute value of floating-point number
39 .BI "double fabs(double " x );
40 .BI "float fabsf(float " x );
41 .BI "long double fabsl(long double " x );
47 Feature Test Macro Requirements for glibc (see
48 .BR feature_test_macros (7)):
54 _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
55 || /* Since glibc 2.19: */ _DEFAULT_SOURCE
56 || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
59 These functions return the absolute value of the floating-point
63 These functions return the absolute value of
68 is a NaN, a NaN is returned.
72 is \-0, +0 is returned.
76 is negative infinity or positive infinity, positive infinity is returned.
80 For an explanation of the terms used in this section, see
88 Interface Attribute Value
93 T} Thread safety MT-Safe
99 C99, POSIX.1-2001, POSIX.1-2008.
101 The variant returning