xref: /openbsd/lib/libc/gen/scandir.3 (revision 78b63d65)
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34.Dd June 4, 1993
35.Dt SCANDIR 3
36.Os
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 \\*(lp*select\\*(rp\\*(lpstruct dirent *\\*(rp" "int \\*(lp*compar\\*(rp\\*(lpconst void *, const void *\\*(rp"
46.Ft int
47.Fn alphasort "const void *d1" "const void *d2"
48.Sh DESCRIPTION
49The
50.Fn scandir
51function reads the directory
52.Fa dirname
53and builds an array of pointers to directory
54entries using
55.Xr malloc 3 .
56It returns the number of entries in the array.
57A pointer to the array of directory entries is stored in the location
58referenced by
59.Fa namelist .
60.Pp
61The
62.Fa select
63parameter is a pointer to a user-supplied subroutine which is called by
64.Fn scandir
65to select which entries are to be included in the array.
66The select routine is passed a
67pointer to a directory entry and should return a non-zero
68value if the directory entry is to be included in the array.
69If
70.Fa select
71is
72.Dv NULL ,
73then all 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
81.Dv NULL ,
82the array is not sorted.
83.Pp
84The
85.Fn alphasort
86function is a routine which can be used for the
87.Fa compar
88parameter to sort the array alphabetically.
89.Pp
90The memory allocated for the array can be deallocated with
91.Xr free 3 ,
92by freeing each pointer in the array and then the array itself.
93.Sh DIAGNOSTICS
94Returns \-1 if the directory cannot be opened for reading or if
95.Xr malloc 3
96cannot allocate enough memory to hold all the data structures.
97.Sh SEE ALSO
98.Xr directory 3 ,
99.Xr malloc 3 ,
100.Xr qsort 3 ,
101.Xr dir 5
102.Sh HISTORY
103The
104.Fn scandir
105and
106.Fn alphasort
107functions appeared in
108.Bx 4.2 .
109