[thirdparty/man-pages.git] / man3 / abs.3

.\" Copyright 1993 David Metcalfe (david@prism.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.\" manual page may be incorrect or out-of-date.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 (faith@cs.unc.edu)
.\" Modified Sat Dec 16 15:02:59 2000, Joseph S. Myers
.\"
.TH ABS 3  2016-03-15 "GNU" "Linux Programmer's Manual"
.SH NAME
abs, labs, llabs, imaxabs \- compute the absolute value of an integer
.SH SYNOPSIS
.nf
.B #include <stdlib.h>
.PP
.BI "int abs(int " j );
.BI "long int labs(long int " j );
.BI "long long int llabs(long long int " j );

.B #include <inttypes.h>
.PP
.BI "intmax_t imaxabs(intmax_t " j );
.fi
.PP
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.PP
.ad l
.BR llabs ():
.RS 4
_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
.RE
.ad
.SH DESCRIPTION
The
.BR abs ()
function computes the absolute value of the integer
argument \fIj\fP.
The
.BR labs (),
.BR llabs ()
and
.BR imaxabs ()
functions compute the absolute value of the argument \fIj\fP of the
appropriate integer type for the function.
.SH RETURN VALUE
Returns the absolute value of the integer argument, of the appropriate
integer type for the function.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.ad l
.TS
allbox;
lb lb lb
l l l.
Interface	Attribute	Value
T{
.BR abs (),
.BR labs (),
.BR llabs (),
.BR imaxabs ()
T}	Thread safety	MT-Safe
.TE
.ad
.SH CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C99, SVr4, 4.3BSD.
.\" POSIX.1 (1996 edition) requires only the
.\" .BR abs ()
.\" function.
C89 only
includes the
.BR abs ()
and
.BR labs ()
functions; the functions
.BR llabs ()
and
.BR imaxabs ()
were added in C99.
.SH NOTES
Trying to take the absolute value of the most negative integer
is not defined.
.PP
The
.BR llabs ()
function is included in glibc since version 2.0.
The
.BR imaxabs ()
function is included in
glibc since version 2.1.1.
.PP
For
.BR llabs ()
to be declared, it may be necessary to define
\fB_ISOC99_SOURCE\fP or \fB_ISOC9X_SOURCE\fP (depending on the
version of glibc) before including any standard headers.
.PP
By default,
GCC handles
.BR abs (),
.BR labs (),
and (since GCC 3.0)
.BR llabs ()
and
.BR imaxabs ()
as built-in functions.
.SH SEE ALSO
.BR cabs (3),
.BR ceil (3),
.BR fabs (3),
.BR floor (3),
.BR rint (3)
Commit	Line	Data
	1	.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
	2	.\"
	3	.\" %%%LICENSE_START(VERBATIM)
	4	.\" Permission is granted to make and distribute verbatim copies of this
	5	.\" manual provided the copyright notice and this permission notice are
	6	.\" preserved on all copies.
	7	.\"
	8	.\" Permission is granted to copy and distribute modified versions of this
	9	.\" manual under the conditions for verbatim copying, provided that the
	10	.\" entire resulting derived work is distributed under the terms of a
	11	.\" permission notice identical to this one.
	12	.\"
	13	.\" Since the Linux kernel and libraries are constantly changing, this
	14	.\" manual page may be incorrect or out-of-date. The author(s) assume no
	15	.\" responsibility for errors or omissions, or for damages resulting from
	16	.\" the use of the information contained herein. The author(s) may not
	17	.\" have taken the same level of care in the production of this manual,
	18	.\" which is licensed free of charge, as they might when working
	19	.\" professionally.
	20	.\"
	21	.\" Formatted or processed versions of this manual, if unaccompanied by
	22	.\" the source, must acknowledge the copyright and authors of this work.
	23	.\" %%%LICENSE_END
	24	.\"
	25	.\" References consulted:
	26	.\" Linux libc source code
	27	.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
	28	.\" 386BSD man pages
	29	.\" Modified Mon Mar 29 22:31:13 1993, David Metcalfe
	30	.\" Modified Sun Jun 6 23:27:50 1993, David Metcalfe
	31	.\" Modified Sat Jul 24 21:45:37 1993, Rik Faith (faith@cs.unc.edu)
	32	.\" Modified Sat Dec 16 15:02:59 2000, Joseph S. Myers
	33	.\"
	34	.TH ABS 3 2016-03-15 "GNU" "Linux Programmer's Manual"
	35	.SH NAME
	36	abs, labs, llabs, imaxabs \- compute the absolute value of an integer
	37	.SH SYNOPSIS
	38	.nf
	39	.B #include <stdlib.h>
	40	.PP
	41	.BI "int abs(int " j );
	42	.BI "long int labs(long int " j );
	43	.BI "long long int llabs(long long int " j );
	44
	45	.B #include <inttypes.h>
	46	.PP
	47	.BI "intmax_t imaxabs(intmax_t " j );
	48	.fi
	49	.PP
	50	.in -4n
	51	Feature Test Macro Requirements for glibc (see
	52	.BR feature_test_macros (7)):
	53	.in
	54	.PP
	55	.ad l
	56	.BR llabs ():
	57	.RS 4
	58	_ISOC99_SOURCE \|\| _POSIX_C_SOURCE\ >=\ 200112L
	59	.RE
	60	.ad
	61	.SH DESCRIPTION
	62	The
	63	.BR abs ()
	64	function computes the absolute value of the integer
	65	argument \fIj\fP.
	66	The
	67	.BR labs (),
	68	.BR llabs ()
	69	and
	70	.BR imaxabs ()
	71	functions compute the absolute value of the argument \fIj\fP of the
	72	appropriate integer type for the function.
	73	.SH RETURN VALUE
	74	Returns the absolute value of the integer argument, of the appropriate
	75	integer type for the function.
	76	.SH ATTRIBUTES
	77	For an explanation of the terms used in this section, see
	78	.BR attributes (7).
	79	.ad l
	80	.TS
	81	allbox;
	82	lb lb lb
	83	l l l.
	84	Interface Attribute Value
	85	T{
	86	.BR abs (),
	87	.BR labs (),
	88	.BR llabs (),
	89	.BR imaxabs ()
	90	T} Thread safety MT-Safe
	91	.TE
	92	.ad
	93	.SH CONFORMING TO
	94	POSIX.1-2001, POSIX.1-2008, C99, SVr4, 4.3BSD.
	95	.\" POSIX.1 (1996 edition) requires only the
	96	.\" .BR abs ()
	97	.\" function.
	98	C89 only
	99	includes the
	100	.BR abs ()
	101	and
	102	.BR labs ()
	103	functions; the functions
	104	.BR llabs ()
	105	and
	106	.BR imaxabs ()
	107	were added in C99.
	108	.SH NOTES
	109	Trying to take the absolute value of the most negative integer
	110	is not defined.
	111	.PP
	112	The
	113	.BR llabs ()
	114	function is included in glibc since version 2.0.
	115	The
	116	.BR imaxabs ()
	117	function is included in
	118	glibc since version 2.1.1.
	119	.PP
	120	For
	121	.BR llabs ()
	122	to be declared, it may be necessary to define
	123	\fB_ISOC99_SOURCE\fP or \fB_ISOC9X_SOURCE\fP (depending on the
	124	version of glibc) before including any standard headers.
	125	.PP
	126	By default,
	127	GCC handles
	128	.BR abs (),
	129	.BR labs (),
	130	and (since GCC 3.0)
	131	.BR llabs ()
	132	and
	133	.BR imaxabs ()
	134	as built-in functions.
	135	.SH SEE ALSO
	136	.BR cabs (3),
	137	.BR ceil (3),
	138	.BR fabs (3),
	139	.BR floor (3),
	140	.BR rint (3)