abs

ABS(3)                     Linux Programmer's Manual                    ABS(3)

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

SYNOPSIS
       #include <stdlib.h>

       int abs(int j);
       long int labs(long int j);
       long long int llabs(long long int j);

       #include <inttypes.h>

       intmax_t imaxabs(intmax_t j);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       llabs():
           _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
           _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99

DESCRIPTION
       The abs() function computes the absolute value of the integer  argument
       j.   The  labs(),  llabs() and imaxabs() functions compute the absolute
       value of the argument j of the appropriate integer type for  the  func-
       tion.

RETURN VALUE
       Returns  the absolute value of the integer argument, of the appropriate
       integer type for the function.

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       +-------------------+---------------+---------+
       |Interface          | Attribute     | Value   |
       +-------------------+---------------+---------+
       |abs(), labs(),     | Thread safety | MT-Safe |
       |llabs(), imaxabs() |               |         |
       +-------------------+---------------+---------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008, C99, SVr4, 4.3BSD.  C89 only  includes  the
       abs()  and  labs()  functions; the functions llabs() and imaxabs() were
       added in C99.

NOTES
       Trying to take the absolute value of the most negative integer  is  not
       defined.

       The llabs() function is included in glibc since version 2.0.  The imax-
       abs() function is included in glibc since version 2.1.1.

       For  llabs()  to  be  declared,  it  may   be   necessary   to   define
       _ISOC99_SOURCE  or  _ISOC9X_SOURCE  (depending on the version of glibc)
       before including any standard headers.

       By default, GCC handles abs(), labs(), and (since GCC 3.0) llabs()  and
       imaxabs() as built-in functions.

SEE ALSO
       cabs(3), ceil(3), fabs(3), floor(3), rint(3)

COLOPHON
       This  page  is  part of release 4.04 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       http://www.kernel.org/doc/man-pages/.

GNU                               2015-08-08                            ABS(3)
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