SCANDIR(3) Library Functions Manual SCANDIR(3)

scandir, scandir_b, alphasort — scan a directory

#include <sys/types.h>
#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
alphasort(const struct dirent **d1, const struct dirent **d2);

int
scandir_b(const char *dirname, struct dirent ***namelist, int (^select)(const struct dirent *), int (^compar)(const struct dirent **, const struct dirent **));

The () 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 (even if the number of entries is 0).

The select argument is a pointer to a user supplied subroutine which is called by () 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 () function is a routine which can be used for the compar argument 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.

The () function works the same way as the scandir() function, except that select and compar are blocks instead of subroutines.

Returns -1 if the directory cannot be opened for reading or if malloc(3) cannot allocate enough memory to hold all the data structures.

directory(3), malloc(3), qsort(3), dir(5)

The scandir() and alphasort() functions appeared in 4.2BSD. The scandir_b() function appeared in Mac OS X 10.6.

May 20, 2008 macOS 14.6