1ABS(3) Linux Programmer's Manual ABS(3)
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6 abs, labs, llabs, imaxabs - compute the absolute value of an integer
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9 #include <stdlib.h>
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11 int abs(int j);
12 long int labs(long int j);
13 long long int llabs(long long int j);
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15 #include <inttypes.h>
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17 intmax_t imaxabs(intmax_t j);
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19 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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21 llabs(): _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99
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24 The abs() function computes the absolute value of the integer argument
25 j. The labs(), llabs() and imaxabs() functions compute the absolute
26 value of the argument j of the appropriate integer type for the func‐
27 tion.
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30 Returns the absolute value of the integer argument, of the appropriate
31 integer type for the function.
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34 SVr4, POSIX.1-2001, 4.3BSD, C99. C89 only includes the abs() and
35 labs() functions; the functions llabs() and imaxabs() were added in
36 C99.
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39 Trying to take the absolute value of the most negative integer is not
40 defined.
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42 The llabs() function is included in glibc since version 2.0, but is not
43 in libc5 or libc4. The imaxabs() function is included in glibc since
44 version 2.1.1.
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46 For llabs() to be declared, it may be necessary to define
47 _ISOC99_SOURCE or _ISOC9X_SOURCE (depending on the version of glibc)
48 before including any standard headers.
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50 GCC handles abs() and labs() as built-in functions. GCC 3.0 also han‐
51 dles llabs() and imaxabs() as built-ins.
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54 cabs(3), ceil(3), fabs(3), floor(3), rint(3)
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57 This page is part of release 3.22 of the Linux man-pages project. A
58 description of the project, and information about reporting bugs, can
59 be found at http://www.kernel.org/doc/man-pages/.
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63GNU 2007-07-26 ABS(3)