xref: /freebsd/lib/libc/gen/scandir.3 (revision a1a4f1a0d87b594d3f17a97dc0127eec1417e6f6)
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32.\"     @(#)scandir.3	8.1 (Berkeley) 6/4/93
33.\" $FreeBSD$
34.\"
35.Dd June 4, 1993
36.Dt SCANDIR 3
37.Os BSD 4.2
38.Sh NAME
39.Nm scandir ,
40.Nm alphasort
41.Nd scan a directory
42.Sh SYNOPSIS
43.Fd #include <sys/types.h>
44.Fd #include <dirent.h>
45.Ft int
46.Fn scandir "const char *dirname" "struct dirent ***namelist" "int \\*(lp*select\\*(rp\\*(lpstruct dirent *\\*(rp" "int \\*(lp*compar\\*(rp\\*(lpconst void *, const void *\\*(rp"
47.Ft int
48.Fn alphasort "const void *d1" "const void *d2"
49.Sh DESCRIPTION
50The
51.Fn scandir
52function
53reads the directory
54.Fa dirname
55and builds an array of pointers to directory
56entries using
57.Xr malloc 3 .
58It returns the number of entries in the array.
59A pointer to the array of directory entries is stored in the location
60referenced by
61.Fa namelist .
62.Pp
63The
64.Fa select
65parameter is a pointer to a user supplied subroutine which is called by
66.Fn scandir
67to select which entries are to be included in the array.
68The select routine is passed a
69pointer to a directory entry and should return a non-zero
70value if the directory entry is to be included in the array.
71If
72.Fa select
73is null, then all the directory entries will be included.
74.Pp
75The
76.Fa compar
77parameter is a pointer to a user supplied subroutine which is passed to
78.Xr qsort 3
79to sort the completed array.
80If this pointer is null, the array is not sorted.
81.Pp
82The
83.Fn alphasort
84function
85is a routine which can be used for the
86.Fa compar
87parameter to sort the array alphabetically.
88.Pp
89The memory allocated for the array can be deallocated with
90.Xr free 3 ,
91by freeing each pointer in the array and then the array itself.
92.Sh DIAGNOSTICS
93Returns \-1 if the directory cannot be opened for reading or if
94.Xr malloc 3
95cannot allocate enough memory to hold all the data structures.
96.Sh SEE ALSO
97.Xr directory 3 ,
98.Xr malloc 3 ,
99.Xr qsort 3 ,
100.Xr dir 5
101.Sh HISTORY
102The
103.Fn scandir
104and
105.Fn alphasort
106functions appeared in
107.Bx 4.2 .
108