SCANDIR(3) BSD Programmer's Manual SCANDIR(3)NAME
scandir, alphasort - scan a directory
SYNOPSIS
#include <sys/types.h>
#include <dirent.h>
int
scandir(const char *dirname, struct dirent ***namelist,
int (*select)(struct dirent *),
int (*compar)(const void *, const void *));
int
alphasort(const void *d1, const void *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 parameter is a pointer to a user supplied subroutine which is
called by scandir() to select which entries are to be included in the ar-
ray. 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(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
parameter to sort the array alphabetically.
The memory allocated for the array can be deallocated with free(3), by
freeing each pointer in the array and then the array itself.
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 ALSOdirectory(3), malloc(3), qsort(3), dir(5)HISTORY
The scandir() and alphasort() functions appeared in 4.2BSD.
BUGS
The scandir() and alphasort() functions may not be safely called concur-
rently from multiple threads, e.g., the interfaces described by
pthreads(3).
4.2 Berkeley Distribution June 4, 1993 1
