llabs(3) - f38

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

6       abs, labs, llabs, imaxabs - compute the absolute value of an integer
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

12       #include <stdlib.h>
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14       int abs(int j);
15       long labs(long j);
16       long long llabs(long long j);
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18       #include <inttypes.h>
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20       intmax_t imaxabs(intmax_t j);
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22   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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24       llabs():
25           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
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DESCRIPTION

28       The  abs() function computes the absolute value of the integer argument
29       j.  The labs(), llabs(), and imaxabs() functions compute  the  absolute
30       value  of  the argument j of the appropriate integer type for the func‐
31       tion.
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RETURN VALUE

34       Returns the absolute value of the integer argument, of the  appropriate
35       integer type for the function.
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ATTRIBUTES

38       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
39       tributes(7).
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41       ┌────────────────────────────────────────────┬───────────────┬─────────┐
42       │Interface                                   │ Attribute     │ Value   │
43       ├────────────────────────────────────────────┼───────────────┼─────────┤
44       │abs(), labs(), llabs(), imaxabs()           │ Thread safety │ MT-Safe │
45       └────────────────────────────────────────────┴───────────────┴─────────┘
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STANDARDS

48       C11, POSIX.1-2008.
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HISTORY

51       POSIX.1-2001, C99, SVr4, 4.3BSD.
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53       C89 only includes the abs() and labs() functions; the functions llabs()
54       and imaxabs() were added in C99.
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NOTES

57       Trying  to  take the absolute value of the most negative integer is not
58       defined.
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60       The llabs() function is included since glibc 2.0.  The imaxabs()  func‐
61       tion is included since glibc 2.1.1.
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63       For   llabs()   to   be   declared,  it  may  be  necessary  to  define
64       _ISOC99_SOURCE or _ISOC9X_SOURCE (depending on the  version  of  glibc)
65       before including any standard headers.
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67       By  default, GCC handles abs(), labs(), and (since GCC 3.0) llabs() and
68       imaxabs() as built-in functions.
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