[apple/libc.git] / stdlib / FreeBSD / lsearch.3

.\"
.\" Initial implementation:
.\" Copyright (c) 2002 Robert Drehmel
.\" All rights reserved.
.\"
.\" As long as the above copyright statement and this notice remain
.\" unchanged, you can do what ever you want with this file.
.\"
.\" $FreeBSD: src/lib/libc/stdlib/lsearch.3,v 1.5 2005/01/20 09:17:04 ru Exp $
.\"
.Dd October 11, 2002
.Dt LSEARCH 3
.Os
.Sh NAME
.Nm lfind ,
.Nm lsearch
.Nd linear search and append
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In search.h
.Ft "void *"
.Fo lfind
.Fa "const void *key" "const void *base" "size_t *nelp" "size_t width"
.Fa "int \*[lp]*compar\*[rp]\*[lp]const void *, const void *\*[rp]"
.Fc
.Ft "void *"
.Fo lsearch
.Fa "const void *key" "void *base" "size_t *nelp" "size_t width"
.Fa "int \*[lp]*compar\*[rp]\*[lp]const void *, const void *\*[rp]"
.Fc
.Sh DESCRIPTION
The
.Fn lsearch
and
.Fn lfind
functions walk linearly through an array, comparing each element with
the one to be sought, by means of a supplied comparison function.
.Pp
The
.Fa key
argument
points to an element that matches the one that is searched.
The array's address in memory is denoted by the
.Fa base
argument.
The width of one element (i.e., the size as returned by
.Fn sizeof )
is passed as the
.Fa width
argument.
The number of valid elements contained in the array (not the number of
elements the array has space reserved for) is given in the integer pointed
to by
.Fa nelp .
The
.Fa compar
argument points to a function which compares its two arguments and returns
zero if they are matching, and non-zero otherwise.
.Pp
If no matching element was found in the array,
.Fn lsearch
copies
.Fa key
into the position after the last element and increments the
integer pointed to by
.Fa nelp .
.Sh RETURN VALUES
The
.Fn lsearch
and
.Fn lfind
functions
return a pointer to the first element found.
If no element was found,
.Fn lsearch
returns a pointer to the newly added element, whereas
.Fn lfind
returns
.Dv NULL .
Both functions return
.Dv NULL
if an error occurs.
.Sh SEE ALSO
.Xr bsearch 3 ,
.Xr hsearch 3 ,
.Xr tsearch 3
.Sh STANDARDS
The
.Fn lsearch
and
.Fn lfind
functions conform to
.St -p1003.1-2001 .
.Sh HISTORY
The
.Fn lsearch
and
.Fn lfind
functions appeared in
.Bx 4.2 .
In
.Fx 5.0 ,
they reappeared conforming to
.St -p1003.1-2001 .
Commit	Line	Data
9385eb3d A	1	.\"
	2	.\" Initial implementation:
	3	.\" Copyright (c) 2002 Robert Drehmel
	4	.\" All rights reserved.
	5	.\"
	6	.\" As long as the above copyright statement and this notice remain
	7	.\" unchanged, you can do what ever you want with this file.
	8	.\"
1f2f436a	9	.\" $FreeBSD: src/lib/libc/stdlib/lsearch.3,v 1.5 2005/01/20 09:17:04 ru Exp $
9385eb3d A	10	.\"
	11	.Dd October 11, 2002
	12	.Dt LSEARCH 3
	13	.Os
	14	.Sh NAME
ad3c9f2a A	15	.Nm lfind ,
ad3c9f2a A	16	.Nm lsearch
9385eb3d A	17	.Nd linear search and append
	18	.Sh LIBRARY
	19	.Lb libc
	20	.Sh SYNOPSIS
	21	.In search.h
	22	.Ft "void *"
ad3c9f2a A	23	.Fo lfind
ad3c9f2a A	24	.Fa "const void key" "const void base" "size_t *nelp" "size_t width"
9385eb3d A	25	.Fa "int \[lp]compar\[rp]\[lp]const void , const void \*[rp]"
	26	.Fc
	27	.Ft "void *"
ad3c9f2a A	28	.Fo lsearch
ad3c9f2a A	29	.Fa "const void key" "void base" "size_t *nelp" "size_t width"
9385eb3d A	30	.Fa "int \[lp]compar\[rp]\[lp]const void , const void \*[rp]"
	31	.Fc
	32	.Sh DESCRIPTION
	33	The
	34	.Fn lsearch
	35	and
	36	.Fn lfind
ad3c9f2a A	37	functions walk linearly through an array, comparing each element with
ad3c9f2a A	38	the one to be sought, by means of a supplied comparison function.
9385eb3d A	39	.Pp
	40	The
	41	.Fa key
	42	argument
	43	points to an element that matches the one that is searched.
	44	The array's address in memory is denoted by the
	45	.Fa base
	46	argument.
	47	The width of one element (i.e., the size as returned by
	48	.Fn sizeof )
	49	is passed as the
	50	.Fa width
	51	argument.
	52	The number of valid elements contained in the array (not the number of
	53	elements the array has space reserved for) is given in the integer pointed
	54	to by
	55	.Fa nelp .
	56	The
	57	.Fa compar
	58	argument points to a function which compares its two arguments and returns
	59	zero if they are matching, and non-zero otherwise.
	60	.Pp
	61	If no matching element was found in the array,
	62	.Fn lsearch
	63	copies
	64	.Fa key
	65	into the position after the last element and increments the
	66	integer pointed to by
	67	.Fa nelp .
	68	.Sh RETURN VALUES
	69	The
	70	.Fn lsearch
	71	and
	72	.Fn lfind
	73	functions
	74	return a pointer to the first element found.
	75	If no element was found,
	76	.Fn lsearch
	77	returns a pointer to the newly added element, whereas
	78	.Fn lfind
	79	returns
	80	.Dv NULL .
	81	Both functions return
	82	.Dv NULL
	83	if an error occurs.
	84	.Sh SEE ALSO
	85	.Xr bsearch 3 ,
	86	.Xr hsearch 3 ,
	87	.Xr tsearch 3
1f2f436a A	88	.Sh STANDARDS
	89	The
	90	.Fn lsearch
	91	and
	92	.Fn lfind
	93	functions conform to
	94	.St -p1003.1-2001 .
9385eb3d A	95	.Sh HISTORY
	96	The
	97	.Fn lsearch
	98	and
	99	.Fn lfind
	100	functions appeared in
	101	.Bx 4.2 .
	102	In
	103	.Fx 5.0 ,
	104	they reappeared conforming to
	105	.St -p1003.1-2001 .