scandir.3

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)scandir.3	8.1	9/11/90
.TH scandir 3 
.SH Name
scandir \- scan a directory
.SH Syntax
.nf
.B #include <sys/types.h>
.B #include <sys/dir.h>
.PP
.B scandir(dirname, namelist, select, compar)
.B char *dirname;
.B struct direct *(*namelist[]);
.B int (*select)();
.B int (*compar)();
.PP
.B alphasort(d1, d2)
.B struct direct **d1, **d2;
.fi
.SH Description
.NXR "scandir subroutine"
.NXR "directory" "scanning"
The
.PN scandir
subroutine reads the directory
.I dirname
and builds an array of pointers to directory
entries using 
.MS malloc 3 .
It returns the number of entries in the array and a pointer to the
array through
.IR namelist .
.PP
The
.I select
parameter is a pointer to a user supplied subroutine which is called by
.PN 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
.I select
is null, then all the directory entries will be included.
.PP
The
.I compar
parameter is a pointer to a user supplied subroutine which is passed to
.MS qsort 3
to sort the completed array.
If this pointer is null, the array is not sorted.
The
.PN alphasort
is a routine which can be used for the
.I compar
parameter to sort the array alphabetically.
.PP
The memory allocated for the array can be deallocated with
.I free
by freeing each pointer in the array and the array itself.
For further information, see 
.MS malloc 3 .
.SH Diagnostics
Returns \-1 if the directory cannot be opened for reading or if
.MS malloc 3
cannot allocate enough memory to hold all the data structures.
.SH See Also
directory(3), malloc(3), qsort(3), dir(5)