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.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" References consulted:
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.\" Linux libc source code
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.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
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.\" 386BSD man pages
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.\" Modified Mon Mar 29 22:31:13 1993, David Metcalfe
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.\" Modified Sun Jun 6 23:27:50 1993, David Metcalfe
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.\" Modified Sat Jul 24 21:45:37 1993, Rik Faith (faith@cs.unc.edu)
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.\" Modified Sat Dec 16 15:02:59 2000, Joseph S. Myers
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.\"
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_exit.2, brk.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, getdtablesize.2, gethostname.2, getpagesize.2, getsid.2, killpg.2, mknod.2, mknodat.2, poll.2, posix_fadvise.2, pread.2, readlink.2, setpgid.2, setreuid.2, sigaltstack.2, stat.2, symlink.2, sync.2, truncate.2, vfork.2, wait.2, wait4.2, a64l.3, abs.3, acos.3, acosh.3, asin.3, asinh.3, atan.3, atan2.3, atoi.3, cbrt.3, ceil.3, copysign.3, cosh.3, dirfd.3, div.3, ecvt.3, erf.3, erfc.3, exp.3, exp2.3, fabs.3, fdim.3, ffs.3, floor.3, fma.3, fmax.3, fmin.3, fmod.3, fpclassify.3, frexp.3, ftw.3, fwide.3, gcvt.3, getcwd.3, getdate.3, getgrent.3, gethostid.3, getpass.3, getpwent.3, getsubopt.3, getw.3, hypot.3, ilogb.3, index.3, isalpha.3, isgreater.3, iswblank.3, j0.3, ldexp.3, lockf.3, log.3, log10.3, log1p.3, logb.3, lrint.3, lround.3, mkstemp.3, mktemp.3, modf.3, mq_receive.3, mq_send.3, nan.3, nextafter.3, posix_fallocate.3, posix_memalign.3, printf.3, qecvt.3, random.3, realpath.3, remainder.3, remquo.3, rint.3, round.3, scalb.3, scalbln.3, scanf.3, siginterrupt.3, signbit.3, sigset.3, sinh.3, sqrt.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strfry.3, strpbrk.3, strsep.3, strspn.3, strstr.3, strtod.3, strtok.3, strtol.3, strtoul.3, strxfrm.3, tanh.3, tgamma.3, trunc.3, ttyslot.3, ualarm.3, usleep.3, wprintf.3, armscii-8.7, cp1251.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-3.7, iso_8859-5.7, iso_8859-6.7, iso_8859-8.7, koi8-u.7: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-19 17:19:13 +00:00
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.TH ABS 3 2010-09-20 "GNU" "Linux Programmer's Manual"
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.SH NAME
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abs, labs, llabs, imaxabs \- compute the absolute value of an integer
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.SH SYNOPSIS
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.nf
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.B #include <stdlib.h>
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.sp
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.BI "int abs(int " j );
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.br
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.BI "long int labs(long int " j );
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.br
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.BI "long long int llabs(long long int " j );
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.sp
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.B #include <inttypes.h>
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.sp
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.BI "intmax_t imaxabs(intmax_t " j );
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.fi
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2007-07-08 12:11:40 +00:00
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.sp
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.sp
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2010-09-18 16:32:42 +00:00
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.ad l
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.BR llabs ():
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.RS 4
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_XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
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_POSIX_C_SOURCE\ >=\ 200112L;
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.br
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or
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.I cc\ -std=c99
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.ad
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.SH DESCRIPTION
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The
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.BR abs ()
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function computes the absolute value of the integer
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argument \fIj\fP.
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The
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.BR labs (),
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.BR llabs ()
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and
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.BR imaxabs ()
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functions compute the absolute value of the argument \fIj\fP of the
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appropriate integer type for the function.
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.SH "RETURN VALUE"
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Returns the absolute value of the integer argument, of the appropriate
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integer type for the function.
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.SH "CONFORMING TO"
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SVr4, POSIX.1-2001, 4.3BSD, C99.
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.\" POSIX.1 (1996 edition) only requires the
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2007-05-12 12:53:57 +00:00
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.\" .BR abs ()
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.\" function.
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2006-08-03 13:57:30 +00:00
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C89 only
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includes the
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.BR abs ()
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and
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.BR labs ()
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functions; the functions
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.BR llabs ()
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and
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.BR imaxabs ()
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were added in C99.
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.SH NOTES
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Trying to take the absolute value of the most negative integer
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is not defined.
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.PP
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The
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.BR llabs ()
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function is included in glibc since version 2.0, but
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is not in libc5 or libc4.
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The
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.BR imaxabs ()
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function is included in
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glibc since version 2.1.1.
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.PP
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For
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.BR llabs ()
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to be declared, it may be necessary to define
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\fB_ISOC99_SOURCE\fP or \fB_ISOC9X_SOURCE\fP (depending on the
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version of glibc) before including any standard headers.
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.PP
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2007-05-12 09:06:04 +00:00
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GCC handles
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.BR abs ()
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and
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.BR labs ()
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as built-in functions.
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GCC 3.0 also handles
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.BR llabs ()
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and
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.BR imaxabs ()
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as built-ins.
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.SH "SEE ALSO"
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2004-11-15 11:59:59 +00:00
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.BR cabs (3),
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.BR ceil (3),
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.BR fabs (3),
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.BR floor (3),
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.BR rint (3)
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