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);
 
[Note] Note
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 function.

RETURN VALUE

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

ATTRIBUTES

Multithreading (see pthreads(7))

The abs(), labs(), llabs(), and imaxabs() functions are thread-safe.

CONFORMING TO

SVr4, POSIX.1-2001, 4.3BSD, C99. 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, but is not in libc5 or libc4. The imaxabs() 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.

GCC handles abs() and labs() as built-in functions. GCC 3.0 also handles llabs() and imaxabs() as built-ins.

SEE ALSO

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

COLOPHON

This page is part of release 3.52 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man−pages/.


  Copyright 1993 David Metcalfe (davidprism.demon.co.uk)

%%%LICENSE_START(VERBATIM)
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Since the Linux kernel and libraries are constantly changing, this
manual page may be incorrect or out-of-date.  The author(s) assume no
responsibility for errors or omissions, or for damages resulting from
the use of the information contained herein.  The author(s) may not
have taken the same level of care in the production of this manual,
which is licensed free of charge, as they might when working
professionally.

Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.
%%%LICENSE_END

References consulted:
    Linux libc source code
    Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
    386BSD man pages
Modified Mon Mar 29 22:31:13 1993, David Metcalfe
Modified Sun Jun  6 23:27:50 1993, David Metcalfe
Modified Sat Jul 24 21:45:37 1993, Rik Faith (faithcs.unc.edu)
Modified Sat Dec 16 15:02:59 2000, Joseph S. Myers