[apple/libc.git] / gen / FreeBSD / scandir.3

.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)scandir.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD: src/lib/libc/gen/scandir.3,v 1.9 2007/01/09 00:27:55 imp Exp $
.\"
.Dd June 4, 1993
.Dt SCANDIR 3
.Os
.Sh NAME
.Nm scandir ,
.Nm alphasort
.Nd scan a directory
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/types.h
.In dirent.h
.Ft int
.Fn scandir "const char *dirname" "struct dirent ***namelist" "int \\*(lp*select\\*(rp\\*(lpstruct dirent *\\*(rp" "int \\*(lp*compar\\*(rp\\*(lpconst void *, const void *\\*(rp"
.Ft int
.Fn alphasort "const void *d1" "const void *d2"
.Sh DESCRIPTION
The
.Fn scandir
function
reads the directory
.Fa dirname
and builds an array of pointers to directory
entries using
.Xr malloc 3 .
It returns the number of entries in the array.
A pointer to the array of directory entries is stored in the location
referenced by
.Fa namelist .
.Pp
The
.Fa select
argument is a pointer to a user supplied subroutine which is called by
.Fn scandir
to select which entries are to be included in the array.
The select routine is passed a
pointer to a directory entry and should return a non-zero
value if the directory entry is to be included in the array.
If
.Fa select
is null, then all the directory entries will be included.
.Pp
The
.Fa compar
argument is a pointer to a user supplied subroutine which is passed to
.Xr qsort 3
to sort the completed array.
If this pointer is null, the array is not sorted.
.Pp
The
.Fn alphasort
function
is a routine which can be used for the
.Fa compar
argument to sort the array alphabetically.
.Pp
The memory allocated for the array can be deallocated with
.Xr free 3 ,
by freeing each pointer in the array and then the array itself.
.Sh DIAGNOSTICS
Returns \-1 if the directory cannot be opened for reading or if
.Xr malloc 3
cannot allocate enough memory to hold all the data structures.
.Sh SEE ALSO
.Xr directory 3 ,
.Xr malloc 3 ,
.Xr qsort 3 ,
.Xr dir 5
.Sh HISTORY
The
.Fn scandir
and
.Fn alphasort
functions appeared in
.Bx 4.2 .
Commit	Line	Data
5b2abdfb	1	.\" Copyright (c) 1983, 1991, 1993
e9ce8d39 A	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
e9ce8d39 A	12	.\" 4. Neither the name of the University nor the names of its contributors
	13	.\" may be used to endorse or promote products derived from this software
	14	.\" without specific prior written permission.
	15	.\"
	16	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	17	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	18	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	19	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	20	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	21	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	22	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	23	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	24	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	25	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	26	.\" SUCH DAMAGE.
	27	.\"
5b2abdfb	28	.\" @(#)scandir.3 8.1 (Berkeley) 6/4/93
1f2f436a	29	.\" $FreeBSD: src/lib/libc/gen/scandir.3,v 1.9 2007/01/09 00:27:55 imp Exp $
e9ce8d39	30	.\"
5b2abdfb A	31	.Dd June 4, 1993
5b2abdfb A	32	.Dt SCANDIR 3
e9ce8d39 A	33	.Os
e9ce8d39 A	34	.Sh NAME
5b2abdfb A	35	.Nm scandir ,
	36	.Nm alphasort
	37	.Nd scan a directory
e9ce8d39 A	38	.Sh LIBRARY
	39	.Lb libc
	40	.Sh SYNOPSIS
5b2abdfb A	41	.In sys/types.h
5b2abdfb A	42	.In dirent.h
e9ce8d39	43	.Ft int
5b2abdfb A	44	.Fn scandir "const char dirname" "struct dirent *namelist" "int \\(lpselect\\(rp\\(lpstruct dirent \\(rp" "int \\(lpcompar\\(rp\\(lpconst void , const void \\(rp"
	45	.Ft int
	46	.Fn alphasort "const void d1" "const void d2"
e9ce8d39 A	47	.Sh DESCRIPTION
e9ce8d39 A	48	The
5b2abdfb A	49	.Fn scandir
	50	function
	51	reads the directory
	52	.Fa dirname
	53	and builds an array of pointers to directory
	54	entries using
	55	.Xr malloc 3 .
	56	It returns the number of entries in the array.
	57	A pointer to the array of directory entries is stored in the location
	58	referenced by
	59	.Fa namelist .
	60	.Pp
	61	The
	62	.Fa select
9385eb3d	63	argument is a pointer to a user supplied subroutine which is called by
5b2abdfb A	64	.Fn scandir
	65	to select which entries are to be included in the array.
	66	The select routine is passed a
	67	pointer to a directory entry and should return a non-zero
	68	value if the directory entry is to be included in the array.
e9ce8d39	69	If
5b2abdfb A	70	.Fa select
	71	is null, then all the directory entries will be included.
	72	.Pp
e9ce8d39	73	The
5b2abdfb	74	.Fa compar
9385eb3d	75	argument is a pointer to a user supplied subroutine which is passed to
5b2abdfb A	76	.Xr qsort 3
	77	to sort the completed array.
	78	If this pointer is null, the array is not sorted.
	79	.Pp
	80	The
	81	.Fn alphasort
	82	function
	83	is a routine which can be used for the
	84	.Fa compar
9385eb3d	85	argument to sort the array alphabetically.
5b2abdfb A	86	.Pp
	87	The memory allocated for the array can be deallocated with
	88	.Xr free 3 ,
	89	by freeing each pointer in the array and then the array itself.
	90	.Sh DIAGNOSTICS
	91	Returns \-1 if the directory cannot be opened for reading or if
	92	.Xr malloc 3
	93	cannot allocate enough memory to hold all the data structures.
e9ce8d39	94	.Sh SEE ALSO
5b2abdfb A	95	.Xr directory 3 ,
	96	.Xr malloc 3 ,
	97	.Xr qsort 3 ,
	98	.Xr dir 5
e9ce8d39 A	99	.Sh HISTORY
e9ce8d39 A	100	The
5b2abdfb A	101	.Fn scandir
	102	and
	103	.Fn alphasort
	104	functions appeared in
	105	.Bx 4.2 .