abs(3)                     Library Functions Manual                     abs(3)

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

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <stdlib.h>

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

       #include <inttypes.h>

       intmax_t imaxabs(intmax_t j);

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

       llabs():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

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
       function.

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 (), llabs (), imaxabs ()       | Thread safety | MT-Safe |
       +--------------------------------------------+---------------+---------+
STANDARDS
       C11, POSIX.1-2008.

HISTORY
       POSIX.1-2001, 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 since glibc 2.0.  The imaxabs()
       function is included since glibc 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)

Linux man-pages 6.7               2023-10-31                            abs(3)