HP-UX Reference (11i v2 07/12) - 3 Library Functions N-Z (vol 7)

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scandir(3C) scandir(3C)
NAME
scandir(), alphasort() - scan a directory
SYNOPSIS
#include <dirent.h>
extern int scandir(
const char *,
struct dirent ***,
int (*) (const struct dirent *),
int (*) (const struct dirent **,
const struct dirent **
)
);
int alphasort(
const struct dirent **d1,
const struct dirent **d2
);
DESCRIPTION
scandir() reads the directory dirname and builds an array of pointers to directory entries using mal-
loc()
(see malloc(3C)). It returns the number of entries in the array and a pointer to the array through
namelist.
The select parameter is a pointer to a user-supplied subroutine which is called by
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 select is null,
then all the directory entries will be included.
The compar parameter is a pointer to a user-supplied subroutine which is passed to qsort(3C) to sort the
completed array. If this pointer is null, the array is not sorted.
alphasort() is a routine which can be
used for the compar parameter to sort the array alphabetically.
The memory allocated for the array can be deallocated with free() (see malloc(3C)) by freeing each
pointer in the array and the array itself.
EXTERNAL INFLUENCES
Locale
The LC_COLLATE category determines the collation ordering used by alphasort() .
The LC_CTYPE category determines the interpretation of bytes in the file name portion of directory
entries as single- and/or multi-byte characters by the alphasort() function.
Results are undefined if the locales specified by the
LC_COLLATE and LC_CTYPE
categories use
different code sets.
International Code Set Support
Single- and multi-byte character code sets are supported for
alphasort() .
RETURN VALUE
scandir() returns −1 if the directory cannot be opened for reading or if malloc() cannot allocate
enough memory to hold all the data structures.
EXAMPLES
The example program below scans the /tmp directory. It does not exclude any entries since select is
NULL. The contents of namelist are sorted by alphasort() . It prints out how many entries are in
/tmp and the sorted entries of the /tmp directory. The memory used by scandir() is returned using
free().
#include <sys/types.h>
#include <stdio.h>
#include <dirent.h>
extern int scandir();
extern int alphasort();
374 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: December 2007 Update