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1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
2 | .\" | |
93015253 | 3 | .\" %%%LICENSE_START(VERBATIM) |
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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. | |
7 | .\" | |
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. | |
c13182ef | 12 | .\" |
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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14 | .\" manual page may be incorrect or out-of-date.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 | |
19 | .\" professionally. | |
c13182ef | 20 | .\" |
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21 | .\" Formatted or processed versions of this manual, if unaccompanied by |
22 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 23 | .\" %%%LICENSE_END |
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24 | .\" |
25 | .\" References consulted: | |
26 | .\" Linux libc source code | |
27 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
28 | .\" 386BSD man pages | |
29 | .\" Modified Mon Mar 29 22:31:13 1993, David Metcalfe | |
30 | .\" Modified Sun Jun 6 23:27:50 1993, David Metcalfe | |
31 | .\" Modified Sat Jul 24 21:45:37 1993, Rik Faith (faith@cs.unc.edu) | |
32 | .\" Modified Sat Dec 16 15:02:59 2000, Joseph S. Myers | |
33 | .\" | |
1d767b55 | 34 | .TH ABS 3 2021-03-22 "GNU" "Linux Programmer's Manual" |
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35 | .SH NAME |
36 | abs, labs, llabs, imaxabs \- compute the absolute value of an integer | |
37 | .SH SYNOPSIS | |
38 | .nf | |
39 | .B #include <stdlib.h> | |
68e4db0a | 40 | .PP |
fea681da | 41 | .BI "int abs(int " j ); |
ae85f653 AC |
42 | .BI "long labs(long " j ); |
43 | .BI "long long llabs(long long " j ); | |
eaa18d3c | 44 | .PP |
fea681da | 45 | .B #include <inttypes.h> |
68e4db0a | 46 | .PP |
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47 | .BI "intmax_t imaxabs(intmax_t " j ); |
48 | .fi | |
68e4db0a | 49 | .PP |
d39ad78f | 50 | .RS -4 |
cc4615cc MK |
51 | Feature Test Macro Requirements for glibc (see |
52 | .BR feature_test_macros (7)): | |
d39ad78f | 53 | .RE |
68e4db0a | 54 | .PP |
cc4615cc | 55 | .BR llabs (): |
9d2adbae | 56 | .nf |
5c10d2c5 | 57 | _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L |
9d2adbae | 58 | .fi |
fea681da | 59 | .SH DESCRIPTION |
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60 | The |
61 | .BR abs () | |
62 | function computes the absolute value of the integer | |
c13182ef | 63 | argument \fIj\fP. |
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64 | The |
65 | .BR labs (), | |
d556548b | 66 | .BR llabs (), |
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67 | and |
68 | .BR imaxabs () | |
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69 | functions compute the absolute value of the argument \fIj\fP of the |
70 | appropriate integer type for the function. | |
47297adb | 71 | .SH RETURN VALUE |
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72 | Returns the absolute value of the integer argument, of the appropriate |
73 | integer type for the function. | |
b6c6e0a3 | 74 | .SH ATTRIBUTES |
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75 | For an explanation of the terms used in this section, see |
76 | .BR attributes (7). | |
77 | .ad l | |
c466875e | 78 | .nh |
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79 | .TS |
80 | allbox; | |
c466875e | 81 | lbx lb lb |
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82 | l l l. |
83 | Interface Attribute Value | |
84 | T{ | |
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85 | .BR abs (), |
86 | .BR labs (), | |
87 | .BR llabs (), | |
b6c6e0a3 | 88 | .BR imaxabs () |
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89 | T} Thread safety MT-Safe |
90 | .TE | |
c466875e | 91 | .hy |
9baacb39 | 92 | .ad |
c466875e | 93 | .sp 1 |
47297adb | 94 | .SH CONFORMING TO |
c5195941 | 95 | POSIX.1-2001, POSIX.1-2008, C99, SVr4, 4.3BSD. |
33a0ccb2 | 96 | .\" POSIX.1 (1996 edition) requires only the |
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97 | .\" .BR abs () |
98 | .\" function. | |
68e1685c | 99 | C89 only |
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100 | includes the |
101 | .BR abs () | |
102 | and | |
103 | .BR labs () | |
104 | functions; the functions | |
105 | .BR llabs () | |
106 | and | |
107 | .BR imaxabs () | |
108 | were added in C99. | |
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109 | .SH NOTES |
110 | Trying to take the absolute value of the most negative integer | |
111 | is not defined. | |
112 | .PP | |
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113 | The |
114 | .BR llabs () | |
2de012be | 115 | function is included in glibc since version 2.0. |
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116 | The |
117 | .BR imaxabs () | |
118 | function is included in | |
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119 | glibc since version 2.1.1. |
120 | .PP | |
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121 | For |
122 | .BR llabs () | |
123 | to be declared, it may be necessary to define | |
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124 | \fB_ISOC99_SOURCE\fP or \fB_ISOC9X_SOURCE\fP (depending on the |
125 | version of glibc) before including any standard headers. | |
126 | .PP | |
63fe5027 | 127 | By default, |
60a90ecd | 128 | GCC handles |
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129 | .BR abs (), |
130 | .BR labs (), | |
131 | and (since GCC 3.0) | |
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132 | .BR llabs () |
133 | and | |
134 | .BR imaxabs () | |
36ad6ae0 | 135 | as built-in functions. |
47297adb | 136 | .SH SEE ALSO |
36268806 | 137 | .BR cabs (3), |
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138 | .BR ceil (3), |
139 | .BR fabs (3), | |
140 | .BR floor (3), | |
141 | .BR rint (3) |