[unix-history] / usr / src / lib / libc / gen / scandir.3

.\" Copyright (c) 1983, 1991 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.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 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	6.8 (Berkeley) 4/19/91
.\"
.Dd April 19, 1991
.Dt SCANDIR 3
.Os BSD 4.2
.Sh NAME
.Nm scandir ,
.Nm alphasort
.Nd scan a directory
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <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
parameter 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
parameter 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
parameter 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
8168e750 WJ	1	.\" Copyright (c) 1983, 1991 Regents of the University of California.
	2	.\" 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.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)scandir.3 6.8 (Berkeley) 4/19/91
	33	.\"
	34	.Dd April 19, 1991
	35	.Dt SCANDIR 3
	36	.Os BSD 4.2
	37	.Sh NAME
	38	.Nm scandir ,
	39	.Nm alphasort
	40	.Nd scan a directory
	41	.Sh SYNOPSIS
	42	.Fd #include <sys/types.h>
	43	.Fd #include <dirent.h>
	44	.Ft int
	45	.Fn scandir "const char dirname" "struct dirent *namelist" "int \\(lpselect\\(rp\\(lpstruct dirent \\(rp" "int \\(lpcompar\\(rp\\(lpconst void , const void \\(rp"
	46	.Ft int
	47	.Fn alphasort "const void d1" "const void d2"
	48	.Sh DESCRIPTION
	49	The
	50	.Fn scandir
	51	function
	52	reads the directory
	53	.Fa dirname
	54	and builds an array of pointers to directory
	55	entries using
	56	.Xr malloc 3 .
	57	It returns the number of entries in the array.
	58	A pointer to the array of directory entries is stored in the location
	59	referenced by
	60	.Fa namelist .
	61	.Pp
	62	The
	63	.Fa select
	64	parameter is a pointer to a user supplied subroutine which is called by
65	.Fn scandir
66	to select which entries are to be included in the array.
67	The select routine is passed a
68	pointer to a directory entry and should return a non-zero
69	value if the directory entry is to be included in the array.
70	If
71	.Fa select
72	is null, then all the directory entries will be included.
73	.Pp
74	The
75	.Fa compar
76	parameter is a pointer to a user supplied subroutine which is passed to
77	.Xr qsort 3
78	to sort the completed array.
79	If this pointer is null, the array is not sorted.
80	.Pp
81	The
82	.Fn alphasort
83	function
84	is a routine which can be used for the
85	.Fa compar
86	parameter to sort the array alphabetically.
87	.Pp
88	The memory allocated for the array can be deallocated with
89	.Xr free 3 ,
90	by freeing each pointer in the array and then the array itself.
91	.Sh DIAGNOSTICS
92	Returns \-1 if the directory cannot be opened for reading or if
93	.Xr malloc 3
94	cannot allocate enough memory to hold all the data structures.
95	.Sh SEE ALSO
96	.Xr directory 3 ,
97	.Xr malloc 3 ,
98	.Xr qsort 3 ,
99	.Xr dir 5
100	.Sh HISTORY
101	The
102	.Fn scandir
103	and
104	.Fn alphasort
105	functions appeared in
106	.Bx 4.2 .