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SCANDIR(3) FreeBSD Library Functions Manual SCANDIR(3)
NAME
scandir, scandirat, scandir_b, alphasort, versionsort - scan a directory
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <dirent.h>
int
scandir(const char *dirname, struct dirent ***namelist,
int (*select)(const struct dirent *),
int (*compar)(const struct dirent **, const struct dirent **));
int
scandirat(int dirfd, const char *dirname, struct dirent ***namelist,
int (*select)(const struct dirent *),
int (*compar)(const struct dirent **, const struct dirent **));
int
scandir_b(const char *dirname, struct dirent ***namelist,
int (^select)(const struct dirent *),
int (^compar)(const struct dirent **, const struct dirent **));
int
alphasort(const struct dirent **d1, const struct dirent **d2);
int
versionsort(const struct dirent **d1, const struct dirent **d2);
DESCRIPTION
The scandir() function reads the directory dirname and builds an array of
pointers to directory entries using 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 namelist.
The select argument 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 argument is a pointer to a user supplied subroutine which is
passed to qsort(3) to sort the completed array. If this pointer is null,
the array is not sorted.
The alphasort() function is a routine which can be used for the compar
argument to sort the array alphabetically using strcoll(3).
The versionsort() function is a routine which can be used for the compar
argument to sort the array naturally using strverscmp(3).
The memory allocated for the array can be deallocated with free(3), by
freeing each pointer in the array and then the array itself.
The scandirat() function is similar to scandir(), but takes an additional
The scandir_b() function behaves in the same way as scandir(), but takes
blocks as arguments instead of function pointers and calls qsort_b()
rather than qsort().
DIAGNOSTICS
Returns -1 if the directory cannot be opened for reading or if malloc(3)
cannot allocate enough memory to hold all the data structures.
SEE ALSO
openat(2), directory(3), malloc(3), qsort(3), strcoll(3), strverscmp(3),
dir(5)
STANDARDS
The versionsort() function is a GNU extension and conforms to no
standard.
HISTORY
The scandir() and alphasort() functions appeared in 4.2BSD. The
scandirat() and versionsort() functions were added in FreeBSD 13.2.
FreeBSD 14.0-RELEASE-p6 August 31, 2023 FreeBSD 14.0-RELEASE-p6